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TDMS Study 88070-04 Pathology Tables

NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05




       Facility:  Battelle Northwest

       Chemical CAS #:  115-11-0007

       Lock Date:  10/05/95

       Cage Range:  All

       Reasons For Removal:    All

       Removal Date Range:     All

       Treatment Groups:       Include All




































Note:  Animals arranged according to CID number

                                                              Page   1


NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 6| 7| 7| 6| 7| 6| 7| 3| 7| 7| 7| 7| 6| 7| 7| 7| 7| 4| 7| 7| 7| 3| 7|             
                             DAY ON TEST   | 3| 3| 3| 0| 3| 2| 3| 0| 3| 2| 3| 3| 3| 3| 6| 3| 0| 3| 3| 4| 3| 3| 3| 7| 3|             
                                           | 5| 5| 9| 9| 5| 1| 5| 8| 5| 2| 5| 5| 5| 5| 7| 5| 9| 5| 5| 9| 5| 5| 5| 8| 5|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|             
    CONTROL                                | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 ALIMENTARY SYSTEM                         |                                                                          |             
                                           |__________________________________________________________________________|             
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Gallbladder                             | +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Rectum                 | I  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +|             
                                           |__________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +|             
                                           |__________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +|             
      Lymphoma Malignant                   |                                                                          |             
                                           |__________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +|             
      Lymphoma Malignant                   |                                                                          |             
                                           |__________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +|             
      Hepatocellular Carcinoma             | X  X                          X        X                                 |             
      Hepatocellular Carcinoma, Multiple   |                                                                          |             
      Hepatocellular Adenoma               |    X        X  X        X                    X        X     X     X     X|             
      Hepatocellular Adenoma, Multiple     | X                                                                        |             
      Hepatocholangiocarcinoma             |                                                                          |             
      Histiocytic Sarcoma                  |                                        X                                 |             
      Lymphoma Malignant                   | X           X                 X                    X                     |             
                                           |__________________________________________________________________________|             
   Mesentery                               |    +  +                                +                          +     +|             
                                           |__________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +|             
      Lymphoma Malignant                   | X                                                                        |             
                                           |__________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +|             
      Lymphoma Malignant                   | X           X           X     X                                          |             
                                           |__________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page   2                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 6| 7| 7| 6| 7| 6| 7| 3| 7| 7| 7| 7| 6| 7| 7| 7| 7| 4| 7| 7| 7| 3| 7|             
                             DAY ON TEST   | 3| 3| 3| 0| 3| 2| 3| 0| 3| 2| 3| 3| 3| 3| 6| 3| 0| 3| 3| 4| 3| 3| 3| 7| 3|             
                                           | 5| 5| 9| 9| 5| 1| 5| 8| 5| 2| 5| 5| 5| 5| 7| 5| 9| 5| 5| 9| 5| 5| 5| 8| 5|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|             
    CONTROL                                | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 ALIMENTARY SYSTEM - cont                  |                                                                          |             
                                           |                                                                          |             
      Lymphoma Malignant                   |                         X                                                |             
                                           |__________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +|             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                                                                      X   |             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |__________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                                                                      X   |             
                                           |__________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  I  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                                                                      X   |             
                                           |__________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +|             
      Adenoma                              |                                                                          |             
                                           |__________________________________________________________________________|             
   Parathyroid Gland                       | +  M  +  +  +  +  M  +  +  +  +  +  M  +  +  +  +  +  +  M  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                                                                          |             
      Pars Distalis, Adenoma               |          X                             X        X     X                 X|             
                                           |__________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +|             
      Follicular Cell, Adenoma             |                   X                                                      |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Clitoral Gland                          | +  +  +  +  +  +  +  +  M  M  +  +  +  +  I  I  +  +  I  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page   3                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 6| 7| 7| 6| 7| 6| 7| 3| 7| 7| 7| 7| 6| 7| 7| 7| 7| 4| 7| 7| 7| 3| 7|             
                             DAY ON TEST   | 3| 3| 3| 0| 3| 2| 3| 0| 3| 2| 3| 3| 3| 3| 6| 3| 0| 3| 3| 4| 3| 3| 3| 7| 3|             
                                           | 5| 5| 9| 9| 5| 1| 5| 8| 5| 2| 5| 5| 5| 5| 7| 5| 9| 5| 5| 9| 5| 5| 5| 8| 5|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|             
    CONTROL                                | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 GENITAL SYSTEM - cont                     |                                                                          |             
                                           |                                                                          |             
   Ovary                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +|             
      Granulosa Cell Tumor Benign          |                                                                          |             
      Histiocytic Sarcoma                  |                                        X                                 |             
      Lymphoma Malignant                   | X           X                 X                                          |             
      Teratoma Benign                      |          X                                                               |             
      Yolk Sac Carcinoma                   |                            X                                             |             
                                           |__________________________________________________________________________|             
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                               X                                          |             
      Polyp Stromal                        |          X                                                               |             
      Polyp Stromal, Multiple              |                                              X                           |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +|             
      Hemangiosarcoma                      |                                                 X                        |             
                                           |__________________________________________________________________________|             
   Lymph Node                              | +           +                       +                                +   |             
      Iliac, Histiocytic Sarcoma           |                                                                          |             
      Iliac, Lymphoma Malignant            | X                                                                    X   |             
      Lumbar, Lymphoma Malignant           |                                                                          |             
      Pancreatic, Lymphoma Malignant       |             X                                                            |             
      Renal, Histiocytic Sarcoma           |                                                                          |             
      Renal, Lymphoma Malignant            |                                                                          |             
                                           |__________________________________________________________________________|             
   Lymph Node, Bronchial                   | +  +  +  +  +  +  +  +  M  +  +  M  +  +  +  +  +  M  +  M  +  +  M  M  +|             
      Lymphoma Malignant                   | X           X                 X                                         X|             
                                           |__________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  +  +  +  +  M  +  +  +  +  +  +  +  M  +  +  +  +  +  M  +  +  M  +|             
      Lymphoma Malignant                   | X           X                 X                       X                 X|             
                                           |__________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  I  +  +  +  +  +  +  A  +|             
      Histiocytic Sarcoma                  |                                        X                                 |             
      Lymphoma Malignant                   | X           X           X     X                       X                 X|             
                                           |__________________________________________________________________________|             
   Lymph Node, Mediastinal                 | +  M  +  M  +  +  M  +  +  M  +  +  +  +  M  +  +  +  M  M  M  +  +  +  +|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page   4                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 6| 7| 7| 6| 7| 6| 7| 3| 7| 7| 7| 7| 6| 7| 7| 7| 7| 4| 7| 7| 7| 3| 7|             
                             DAY ON TEST   | 3| 3| 3| 0| 3| 2| 3| 0| 3| 2| 3| 3| 3| 3| 6| 3| 0| 3| 3| 4| 3| 3| 3| 7| 3|             
                                           | 5| 5| 9| 9| 5| 1| 5| 8| 5| 2| 5| 5| 5| 5| 7| 5| 9| 5| 5| 9| 5| 5| 5| 8| 5|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|             
    CONTROL                                | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |             
                                           |                                                                          |             
      Histiocytic Sarcoma                  |                                                                          |             
      Lymphoma Malignant                   | X           X                                      X                 X  X|             
                                           |__________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemangiosarcoma                      |                                                 X                        |             
      Hepatocholangiocarcinoma, Metastatic,|                                                                          |             
           Liver                           |                                                                          |             
      Histiocytic Sarcoma                  |                                                                          |             
      Lymphoma Malignant                   | X  X        X           X     X                    X                 X  X|             
                                           |__________________________________________________________________________|             
   Thymus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  A  +|             
      Histiocytic Sarcoma                  |                                                                          |             
      Lymphoma Malignant                   | X           X        X  X     X                                         X|             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |__________________________________________________________________________|             
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  I  +  +  +  +  +  +|             
      Carcinoma                            |          X                                                               |             
                                           |__________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Subcutaneous Tissue, Sarcoma         |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Astrocytoma Benign                   |                                                          X               |             
      Lymphoma Malignant                   | X                                                                    X   |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |__________________________________________________________________________|             
   Larynx                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page   5                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 6| 7| 7| 6| 7| 6| 7| 3| 7| 7| 7| 7| 6| 7| 7| 7| 7| 4| 7| 7| 7| 3| 7|             
                             DAY ON TEST   | 3| 3| 3| 0| 3| 2| 3| 0| 3| 2| 3| 3| 3| 3| 6| 3| 0| 3| 3| 4| 3| 3| 3| 7| 3|             
                                           | 5| 5| 9| 9| 5| 1| 5| 8| 5| 2| 5| 5| 5| 5| 7| 5| 9| 5| 5| 9| 5| 5| 5| 8| 5|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|             
    CONTROL                                | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 RESPIRATORY SYSTEM - cont                 |                                                                          |             
                                           |                                                                          |             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Alveolar/Bronchiolar Adenoma         | X                                                                        |             
      Alveolar/Bronchiolar Carcinoma       |       X                                   X     X                        |             
      Carcinoma, Metastatic, Mammary Gland |                                                                          |             
      Hepatocellular Carcinoma, Metastatic,|                                                                          |             
           Liver                           |    X                                                                     |             
      Histiocytic Sarcoma                  |                                        X                                 |             
      Lymphoma Malignant                   | X           X                                                        X   |             
                                           |__________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +|             
      Lymphoma Malignant                   |                               X                                          |             
                                           |__________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Eye                                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Harderian Gland                         |                                                                          |             
      Adenoma                              |                                                                          |             
      Bilateral, Carcinoma                 |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +|             
      Lymphoma Malignant                   | X                                                                        |             
                                           |__________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   | X           X           X                                            X   |             
 __________________________________________|__________________________________________________________________________|             
 SYSTEMIC LESIONS                          |                                                                          |             
                                            __________________________________________________________________________|             
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Histiocytic Sarcoma                  |                                        X                                 |             
      Lymphoma Malignant                   | X  X        X        X  X     X                    X  X              X  X|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page   6                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 6| 7| 7| 7| 6| 7| 7| 7| 7| 7| 5| 7| 6| 2| 7| 7| 7| 6| 7| 7| 5| 7| 7| 7|            |
                             DAY ON TEST   | 2| 5| 3| 3| 3| 8| 3| 3| 3| 3| 3| 4| 3| 1| 3| 3| 3| 3| 6| 3| 3| 8| 3| 2| 3|            |
                                           | 3| 3| 5| 5| 6| 1| 6| 6| 6| 6| 6| 1| 6| 0| 0| 6| 6| 6| 7| 6| 6| 0| 6| 3| 6|            |
 __________________________________________|__________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|     A      |
    CONTROL                                | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|     L      |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 ALIMENTARY SYSTEM                         |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +|  49        |
                                           |__________________________________________________________________________|____________|
   Gallbladder                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  I|  46        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  A  +  +  A  +  +  +  +  +  +  +  +  +  +|  46        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  A  +  +  A  +  +  +  +  +  +  +  +  +  +|  45        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  A  +  +  A  +  +  +  +  +  +  +  +  +  +|  46        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  A  +  +  A  +  +  +  +  +  +  +  +  +  +|  46        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  A  +  +  A  +  +  +  +  +  +  +  +  +  +|  46        |
      Lymphoma Malignant                   |                                                                X         |          1 |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  A  +  +  A  +  +  +  +  +  +  +  +  +  +|  46        |
      Lymphoma Malignant                   |    X                                                                     |          1 |
                                           |__________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +|  47        |
      Hepatocellular Carcinoma             |                                                                          |          4 |
      Hepatocellular Carcinoma, Multiple   |                                        X                                 |          1 |
      Hepatocellular Adenoma               | X  X  X                                            X  X                 X|         15 |
      Hepatocellular Adenoma, Multiple     |             X     X  X                                      X            |          5 |
      Hepatocholangiocarcinoma             |                                        X                                 |          1 |
      Histiocytic Sarcoma                  |                               X                                          |          2 |
      Lymphoma Malignant                   |                                              X                           |          5 |
                                           |__________________________________________________________________________|____________|
   Mesentery                               |                                                       +  +               |   7        |
                                           |__________________________________________________________________________|____________|
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +|  47        |
      Lymphoma Malignant                   |          X                                                               |          2 |
                                           |__________________________________________________________________________|____________|
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                                                                                                    
                                                                                                                                    
                                                             Page   7                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 6| 7| 7| 7| 6| 7| 7| 7| 7| 7| 5| 7| 6| 2| 7| 7| 7| 6| 7| 7| 5| 7| 7| 7|            |
                             DAY ON TEST   | 2| 5| 3| 3| 3| 8| 3| 3| 3| 3| 3| 4| 3| 1| 3| 3| 3| 3| 6| 3| 3| 8| 3| 2| 3|            |
                                           | 3| 3| 5| 5| 6| 1| 6| 6| 6| 6| 6| 1| 6| 0| 0| 6| 6| 6| 7| 6| 6| 0| 6| 3| 6|            |
 __________________________________________|__________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|     A      |
    CONTROL                                | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|     L      |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 ALIMENTARY SYSTEM - cont                  |                                                                          |            |
                                           |                                                                          |            |
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +|  48        |
      Lymphoma Malignant                   |                                                                          |          4 |
                                           |__________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +|  48        |
      Lymphoma Malignant                   |                                                                          |          1 |
                                           |__________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  A  +  +  A  +  +  +  +  +  +  +  +  +  +|  46        |
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Lymphoma Malignant                   |          X                                                               |          2 |
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +|  49        |
      Lymphoma Malignant                   |                                                                          |          1 |
                                           |__________________________________________________________________________|____________|
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +|  48        |
      Lymphoma Malignant                   |                                                                          |          1 |
                                           |__________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +|  47        |
      Adenoma                              |                X                                                         |          1 |
                                           |__________________________________________________________________________|____________|
   Parathyroid Gland                       | M  +  +  M  M  +  +  M  +  +  M  M  +  M  A  +  +  +  M  M  +  +  +  M  +|  35        |
                                           |__________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +|  49        |
      Lymphoma Malignant                   |                                              X                           |          1 |
      Pars Distalis, Adenoma               |                      X              X                             X      |          8 |
                                           |__________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +|  48        |
      Follicular Cell, Adenoma             |                                                                          |          1 |
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
    None                                   |                                                                          |            |
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                                                                                                    
                                                             Page   8                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 6| 7| 7| 7| 6| 7| 7| 7| 7| 7| 5| 7| 6| 2| 7| 7| 7| 6| 7| 7| 5| 7| 7| 7|            |
                             DAY ON TEST   | 2| 5| 3| 3| 3| 8| 3| 3| 3| 3| 3| 4| 3| 1| 3| 3| 3| 3| 6| 3| 3| 8| 3| 2| 3|            |
                                           | 3| 3| 5| 5| 6| 1| 6| 6| 6| 6| 6| 1| 6| 0| 0| 6| 6| 6| 7| 6| 6| 0| 6| 3| 6|            |
 __________________________________________|__________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|     A      |
    CONTROL                                | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|     L      |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 GENITAL SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Clitoral Gland                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +|  44        |
                                           |__________________________________________________________________________|____________|
   Ovary                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +|  48        |
      Granulosa Cell Tumor Benign          |                                                 X                        |          1 |
      Histiocytic Sarcoma                  |                               X                                          |          2 |
      Lymphoma Malignant                   |          X                                                               |          4 |
      Teratoma Benign                      |                                                                          |          1 |
      Yolk Sac Carcinoma                   |                                                                          |          1 |
                                           |__________________________________________________________________________|____________|
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +|  49        |
      Lymphoma Malignant                   |                                                                          |          1 |
      Polyp Stromal                        |             X                                                            |          2 |
      Polyp Stromal, Multiple              |                                                                          |          1 |
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +|  48        |
      Hemangiosarcoma                      |                                                                          |          1 |
                                           |__________________________________________________________________________|____________|
   Lymph Node                              |    +     +                    +                                          |   7        |
      Iliac, Histiocytic Sarcoma           |                               X                                          |          1 |
      Iliac, Lymphoma Malignant            |    X                                                                     |          3 |
      Lumbar, Lymphoma Malignant           |          X                                                               |          1 |
      Pancreatic, Lymphoma Malignant       |                                                                          |          1 |
      Renal, Histiocytic Sarcoma           |                               X                                          |          1 |
      Renal, Lymphoma Malignant            |    X     X                                                               |          2 |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Bronchial                   | M  +  +  +  +  +  M  +  +  +  M  M  +  +  A  +  +  +  +  +  +  +  +  M  +|  38        |
      Lymphoma Malignant                   |    X     X                                      X              X         |          8 |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | M  +  +  +  +  +  M  +  +  +  M  +  +  +  A  +  +  M  +  +  +  +  +  +  +|  41        |
      Lymphoma Malignant                   |    X     X                                      X                        |          8 |
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                                                                                                    
                                                                                                                                    
                                                             Page   9                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 6| 7| 7| 7| 6| 7| 7| 7| 7| 7| 5| 7| 6| 2| 7| 7| 7| 6| 7| 7| 5| 7| 7| 7|            |
                             DAY ON TEST   | 2| 5| 3| 3| 3| 8| 3| 3| 3| 3| 3| 4| 3| 1| 3| 3| 3| 3| 6| 3| 3| 8| 3| 2| 3|            |
                                           | 3| 3| 5| 5| 6| 1| 6| 6| 6| 6| 6| 1| 6| 0| 0| 6| 6| 6| 7| 6| 6| 0| 6| 3| 6|            |
 __________________________________________|__________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|     A      |
    CONTROL                                | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|     L      |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |            |
                                           |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +|  46        |
      Histiocytic Sarcoma                  |                               X                                          |          2 |
      Lymphoma Malignant                   |    X     X                                   X  X              X         |         11 |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mediastinal                 | +  +  +  +  +  +  +  M  M  +  +  +  +  +  A  +  +  +  +  +  M  +  +  +  +|  38        |
      Histiocytic Sarcoma                  |                               X                                          |          1 |
      Lymphoma Malignant                   |    X     X                                      X              X         |          9 |
                                           |__________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +|  49        |
      Hemangiosarcoma                      |                               X                 X                        |          3 |
      Hepatocholangiocarcinoma, Metastatic,|                                                                          |            |
           Liver                           |                                        X                                 |          1 |
      Histiocytic Sarcoma                  |                               X                                          |          1 |
      Lymphoma Malignant                   |    X                                         X  X  X           X         |         13 |
                                           |__________________________________________________________________________|____________|
   Thymus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +|  47        |
      Histiocytic Sarcoma                  |                               X                                          |          1 |
      Lymphoma Malignant                   |    X     X                                   X                 X         |         10 |
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +|  48        |
      Carcinoma                            |                                  X                                       |          2 |
                                           |__________________________________________________________________________|____________|
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +|  49        |
      Subcutaneous Tissue, Sarcoma         | X                                                     X                  |          2 |
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
                                                                                                                                    
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                                                                                                    
                                                                                                                                    
                                                             Page  10                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 6| 7| 7| 7| 6| 7| 7| 7| 7| 7| 5| 7| 6| 2| 7| 7| 7| 6| 7| 7| 5| 7| 7| 7|            |
                             DAY ON TEST   | 2| 5| 3| 3| 3| 8| 3| 3| 3| 3| 3| 4| 3| 1| 3| 3| 3| 3| 6| 3| 3| 8| 3| 2| 3|            |
                                           | 3| 3| 5| 5| 6| 1| 6| 6| 6| 6| 6| 1| 6| 0| 0| 6| 6| 6| 7| 6| 6| 0| 6| 3| 6|            |
 __________________________________________|__________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|     A      |
    CONTROL                                | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|     L      |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +|  49        |
      Astrocytoma Benign                   |                                                                          |          1 |
      Lymphoma Malignant                   |                                                                          |          2 |
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Larynx                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +|  49        |
                                           |__________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +|  49        |
      Alveolar/Bronchiolar Adenoma         |    X                                                                     |          2 |
      Alveolar/Bronchiolar Carcinoma       |                   X                                                      |          4 |
      Carcinoma, Metastatic, Mammary Gland |                                  X                                       |          1 |
      Hepatocellular Carcinoma, Metastatic,|                                                                          |            |
           Liver                           |                                                                          |          1 |
      Histiocytic Sarcoma                  |                               X                                          |          2 |
      Lymphoma Malignant                   |    X     X                                   X                 X         |          7 |
                                           |__________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +|  47        |
      Lymphoma Malignant                   |                                                                          |          1 |
                                           |__________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +|  48        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Eye                                     |                                                                      +   |   1        |
                                           |__________________________________________________________________________|____________|
   Harderian Gland                         | +                                                                    +   |   2        |
      Adenoma                              | X                                                                        |          1 |
      Bilateral, Carcinoma                 |                                                                      X   |          1 |
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                                                                                                    
                                                                                                                                    
                                                             Page  11                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 6| 7| 7| 7| 6| 7| 7| 7| 7| 7| 5| 7| 6| 2| 7| 7| 7| 6| 7| 7| 5| 7| 7| 7|            |
                             DAY ON TEST   | 2| 5| 3| 3| 3| 8| 3| 3| 3| 3| 3| 4| 3| 1| 3| 3| 3| 3| 6| 3| 3| 8| 3| 2| 3|            |
                                           | 3| 3| 5| 5| 6| 1| 6| 6| 6| 6| 6| 1| 6| 0| 0| 6| 6| 6| 7| 6| 6| 0| 6| 3| 6|            |
 __________________________________________|__________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|     A      |
    CONTROL                                | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|     L      |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 URINARY SYSTEM - cont                     |                                                                          |            |
                                           |                                                                          |            |
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Lymphoma Malignant                   |    X     X                                   X                           |          4 |
                                           |__________________________________________________________________________|____________|
   Urinary Bladder                         | +  I  +  M  +  +  +  +  +  +  +  A  +  +  A  +  +  +  +  +  +  +  +  +  +|  45        |
      Lymphoma Malignant                   |                                                                          |          4 |
 __________________________________________________________________________________________________________________________________ 
 SYSTEMIC LESIONS                          |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Histiocytic Sarcoma                  |                               X                                          |          2 |
      Lymphoma Malignant                   |    X     X                                   X  X  X           X         |         16 |
 __________________________________________________________________________________________________________________________________ 
                                                                                                                                    
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  12                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 6| 6| 6| 7| 7| 7| 6| 6| 6| 7| 7| 7| 7| 5| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7|             
                             DAY ON TEST   | 3| 3| 9| 4| 3| 3| 3| 9| 9| 5| 2| 3| 3| 3| 0| 3| 3| 1| 3| 3| 3| 3| 3| 3| 3|             
                                           | 5| 9| 5| 9| 5| 5| 5| 5| 1| 3| 7| 1| 5| 5| 6| 5| 5| 1| 5| 5| 5| 5| 5| 5| 5|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|             
    500 PPM                                | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 ALIMENTARY SYSTEM                         |                                                                          |             
                                           |__________________________________________________________________________|             
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Gallbladder                             | +  +  +  A  +  +  +  M  M  +  +  A  +  +  A  +  M  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  A  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  A  +  +  +  +  I  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  A  +  +  +  +  +  +  +  A  +  +  A  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  A  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  A  +  +  +  +  +  +  +  A  +  +  A  +  +  +  +  +  +  +  +  +  +|             
      Carcinoma                            |                                                                          |             
      Lymphoma Malignant                   |                                                                          |             
                                           |__________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  A  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hepatoblastoma                       |       X                                                                  |             
      Hepatoblastoma, Multiple             |                                                                   X      |             
      Hepatocellular Carcinoma             |    X     X                                      X     X                  |             
      Hepatocellular Adenoma               |       X     X  X  X  X     X           X        X        X  X        X   |             
      Hepatocellular Adenoma, Multiple     |                                              X     X              X     X|             
      Histiocytic Sarcoma                  |                                                                          |             
      Lymphoma Malignant                   | X           X           X                 X                              |             
                                           |__________________________________________________________________________|             
   Mesentery                               |             +                                         +                 +|             
      Histiocytic Sarcoma                  |                                                                          |             
                                           |__________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   | X                       X                 X                              |             
                                           |__________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   | X                                         X                              |             
                                           |__________________________________________________________________________|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  13                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 6| 6| 6| 7| 7| 7| 6| 6| 6| 7| 7| 7| 7| 5| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7|             
                             DAY ON TEST   | 3| 3| 9| 4| 3| 3| 3| 9| 9| 5| 2| 3| 3| 3| 0| 3| 3| 1| 3| 3| 3| 3| 3| 3| 3|             
                                           | 5| 9| 5| 9| 5| 5| 5| 5| 1| 3| 7| 1| 5| 5| 6| 5| 5| 1| 5| 5| 5| 5| 5| 5| 5|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|             
    500 PPM                                | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 ALIMENTARY SYSTEM - cont                  |                                                                          |             
                                           |                                                                          |             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                         X                                                |             
                                           |__________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  A  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   | X                                                                        |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Histiocytic Sarcoma                  |                                                                          |             
      Lymphoma Malignant                   | X                                         X                              |             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |__________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Histiocytic Sarcoma                  |                                                                          |             
      Lymphoma Malignant                   |                         X                 X                              |             
      Capsule, Adenoma                     |                                                                      X  X|             
                                           |__________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                         X                                                |             
      Pheochromocytoma Benign              |                                                                          |             
                                           |__________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Adenoma                              |                                                                          |             
                                           |__________________________________________________________________________|             
   Parathyroid Gland                       | +  +  +  M  +  +  M  M  +  +  M  +  M  +  M  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Pars Distalis, Adenoma               |    X              X  X              X        X  X        X               |             
                                           |__________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Follicular Cell, Adenoma             |                      X                       X           X               |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
    None                                   |                                                                          |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  14                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 6| 6| 6| 7| 7| 7| 6| 6| 6| 7| 7| 7| 7| 5| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7|             
                             DAY ON TEST   | 3| 3| 9| 4| 3| 3| 3| 9| 9| 5| 2| 3| 3| 3| 0| 3| 3| 1| 3| 3| 3| 3| 3| 3| 3|             
                                           | 5| 9| 5| 9| 5| 5| 5| 5| 1| 3| 7| 1| 5| 5| 6| 5| 5| 1| 5| 5| 5| 5| 5| 5| 5|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|             
    500 PPM                                | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Clitoral Gland                          | +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Ovary                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cystadenoma                          |                               X                                         X|             
      Granulosa Cell Tumor Benign          |                                                 X                        |             
      Hemangioma                           | X                                                                        |             
      Histiocytic Sarcoma                  |                                                                          |             
      Lymphoma Malignant                   | X                       X                 X                              |             
                                           |__________________________________________________________________________|             
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Histiocytic Sarcoma                  |                                                                          |             
      Lymphoma Malignant                   | X                                                                        |             
      Polyp Stromal                        |                                                                          |             
                                           |__________________________________________________________________________|             
   Vagina                                  |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +|             
      Histiocytic Sarcoma                  |                                                                          |             
      Lymphoma Malignant                   | X                                                                        |             
                                           |__________________________________________________________________________|             
   Lymph Node                              |                                                                          |             
      Iliac, Histiocytic Sarcoma           |                                                                          |             
      Renal, Histiocytic Sarcoma           |                                                                          |             
                                           |__________________________________________________________________________|             
   Lymph Node, Bronchial                   | +  +  +  +  +  +  +  +  +  M  M  +  +  M  +  M  +  +  +  +  +  +  +  M  +|             
      Histiocytic Sarcoma                  |                                                                          |             
      Lymphoma Malignant                   | X                       X                 X                              |             
                                           |__________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  M|             
      Histiocytic Sarcoma                  |                                                                          |             
      Lymphoma Malignant                   | X                       X                 X                              |             
                                           |__________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Histiocytic Sarcoma                  |                                                                          |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  15                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 6| 6| 6| 7| 7| 7| 6| 6| 6| 7| 7| 7| 7| 5| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7|             
                             DAY ON TEST   | 3| 3| 9| 4| 3| 3| 3| 9| 9| 5| 2| 3| 3| 3| 0| 3| 3| 1| 3| 3| 3| 3| 3| 3| 3|             
                                           | 5| 9| 5| 9| 5| 5| 5| 5| 1| 3| 7| 1| 5| 5| 6| 5| 5| 1| 5| 5| 5| 5| 5| 5| 5|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|             
    500 PPM                                | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |             
                                           |                                                                          |             
      Lymphoma Malignant                   | X                       X                 X                              |             
                                           |__________________________________________________________________________|             
   Lymph Node, Mediastinal                 | +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  M  +  +  +  +  +|             
      Histiocytic Sarcoma                  |                                                                          |             
      Lymphoma Malignant                   | X                       X                 X                              |             
                                           |__________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Histiocytic Sarcoma                  |                                                                          |             
      Lymphoma Malignant                   | X           X           X                 X                          X   |             
                                           |__________________________________________________________________________|             
   Thymus                                  | +  +  +  +  +  +  +  +  M  +  M  +  +  +  +  +  +  +  +  M  +  +  +  +  +|             
      Lymphoma Malignant                   | X                                         X                              |             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |__________________________________________________________________________|             
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Subcutaneous Tissue, Fibrosarcoma    |                                        X                                 |             
      Subcutaneous Tissue, Fibrous         |                                                                          |             
          Histiocytoma                     |                                                       X                  |             
      Subcutaneous Tissue, Hemangiosarcoma |                                                                          |             
      Subcutaneous Tissue, Sarcoma         |                                                    X                     |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                                           X                              |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |__________________________________________________________________________|             
   Larynx                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  16                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 6| 6| 6| 7| 7| 7| 6| 6| 6| 7| 7| 7| 7| 5| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7|             
                             DAY ON TEST   | 3| 3| 9| 4| 3| 3| 3| 9| 9| 5| 2| 3| 3| 3| 0| 3| 3| 1| 3| 3| 3| 3| 3| 3| 3|             
                                           | 5| 9| 5| 9| 5| 5| 5| 5| 1| 3| 7| 1| 5| 5| 6| 5| 5| 1| 5| 5| 5| 5| 5| 5| 5|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|             
    500 PPM                                | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 RESPIRATORY SYSTEM - cont                 |                                                                          |             
                                           |                                                                          |             
                                           |__________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Alveolar/Bronchiolar Adenoma         |    X                                                                     |             
      Alveolar/Bronchiolar Carcinoma       |                                                                          |             
      Alveolar/Bronchiolar Carcinoma,      |                                                                          |             
          Metastatic, Lung                 |                                                                          |             
      Hepatoblastoma, Metastatic, Liver    |       X                                                                  |             
      Hepatocellular Carcinoma, Metastatic,|                                                                          |             
           Liver                           |    X     X                                                               |             
      Histiocytic Sarcoma                  |                                                                          |             
      Lymphoma Malignant                   | X                       X                 X                              |             
      Sarcoma, Metastatic, Skin            |                                                                          |             
                                           |__________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                                           X                              |             
                                           |__________________________________________________________________________|             
   Pleura                                  |       +                                                                  |             
      Hepatoblastoma, Metastatic, Liver    |       X                                                                  |             
                                           |__________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Eye                                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Harderian Gland                         |                                                                          |             
      Adenoma                              |                                                                          |             
      Carcinoma                            |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Histiocytic Sarcoma                  |                                                                          |             
      Lymphoma Malignant                   | X                       X                 X                              |             
                                           |__________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  17                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 6| 6| 6| 7| 7| 7| 6| 6| 6| 7| 7| 7| 7| 5| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7|             
                             DAY ON TEST   | 3| 3| 9| 4| 3| 3| 3| 9| 9| 5| 2| 3| 3| 3| 0| 3| 3| 1| 3| 3| 3| 3| 3| 3| 3|             
                                           | 5| 9| 5| 9| 5| 5| 5| 5| 1| 3| 7| 1| 5| 5| 6| 5| 5| 1| 5| 5| 5| 5| 5| 5| 5|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|             
    500 PPM                                | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 URINARY SYSTEM - cont                     |                                                                          |             
                                           |                                                                          |             
      Histiocytic Sarcoma                  |                                                                          |             
      Lymphoma Malignant                   | X                                         X                              |             
 __________________________________________|__________________________________________________________________________|             
 SYSTEMIC LESIONS                          |                                                                          |             
                                            __________________________________________________________________________|             
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Histiocytic Sarcoma                  |                                                                          |             
      Lymphoma Malignant                   | X           X           X                 X                          X   |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  18                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 6| 7| 6| 4| 6| 7| 7| 7| 7| 5| 5| 6| 7| 7| 7| 7| 7| 7| 5| 6| 7| 7| 7| 7| 7|            |
                             DAY ON TEST   | 5| 3| 1| 8| 3| 3| 3| 3| 3| 7| 9| 3| 3| 3| 3| 3| 3| 3| 6| 1| 3| 3| 3| 3| 3|            |
                                           | 3| 6| 1| 3| 9| 6| 6| 6| 6| 2| 4| 9| 6| 6| 6| 6| 6| 6| 7| 5| 6| 6| 6| 6| 6|            |
 __________________________________________|__________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|     A      |
    500 PPM                                | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|     L      |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 ALIMENTARY SYSTEM                         |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Gallbladder                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M|  43        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  I  +  +  I  +  +|  45        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  47        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  47        |
      Carcinoma                            |       X                                                                  |          1 |
      Lymphoma Malignant                   |                                        X                                 |          1 |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
                                           |__________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hepatoblastoma                       |                                                                          |          1 |
      Hepatoblastoma, Multiple             |                                                                          |          1 |
      Hepatocellular Carcinoma             |       X     X                                         X                 X|          8 |
      Hepatocellular Adenoma               | X  X                    X              X        X  X                    X|         18 |
      Hepatocellular Adenoma, Multiple     |                                                                          |          4 |
      Histiocytic Sarcoma                  | X                    X                    X              X               |          4 |
      Lymphoma Malignant                   |                                        X                                 |          5 |
                                           |__________________________________________________________________________|____________|
   Mesentery                               |          +                                +     +                 +  +   |   8        |
      Histiocytic Sarcoma                  |                                           X                              |          1 |
                                           |__________________________________________________________________________|____________|
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Lymphoma Malignant                   |                                                                          |          3 |
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                                                                                                    
                                                                                                                                    
                                                             Page  19                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 6| 7| 6| 4| 6| 7| 7| 7| 7| 5| 5| 6| 7| 7| 7| 7| 7| 7| 5| 6| 7| 7| 7| 7| 7|            |
                             DAY ON TEST   | 5| 3| 1| 8| 3| 3| 3| 3| 3| 7| 9| 3| 3| 3| 3| 3| 3| 3| 6| 1| 3| 3| 3| 3| 3|            |
                                           | 3| 6| 1| 3| 9| 6| 6| 6| 6| 2| 4| 9| 6| 6| 6| 6| 6| 6| 7| 5| 6| 6| 6| 6| 6|            |
 __________________________________________|__________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|     A      |
    500 PPM                                | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|     L      |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 ALIMENTARY SYSTEM - cont                  |                                                                          |            |
                                           |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Lymphoma Malignant                   |                                                                          |          2 |
                                           |__________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Lymphoma Malignant                   |                                                                          |          1 |
                                           |__________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
      Lymphoma Malignant                   |                                                                          |          1 |
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Histiocytic Sarcoma                  | X                                                                        |          1 |
      Lymphoma Malignant                   |                                                                          |          2 |
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Histiocytic Sarcoma                  |                                           X                              |          1 |
      Lymphoma Malignant                   |                                                                          |          2 |
      Capsule, Adenoma                     |                                                                          |          2 |
                                           |__________________________________________________________________________|____________|
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Lymphoma Malignant                   |                                                                          |          1 |
      Pheochromocytoma Benign              |                                  X                                       |          1 |
                                           |__________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Adenoma                              |                               X                                          |          1 |
                                           |__________________________________________________________________________|____________|
   Parathyroid Gland                       | +  M  +  M  +  +  +  +  +  +  M  +  +  +  M  +  +  +  M  +  +  +  +  +  +|  39        |
                                           |__________________________________________________________________________|____________|
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                                                                                                    
                                                                                                                                    
                                                             Page  20                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 6| 7| 6| 4| 6| 7| 7| 7| 7| 5| 5| 6| 7| 7| 7| 7| 7| 7| 5| 6| 7| 7| 7| 7| 7|            |
                             DAY ON TEST   | 5| 3| 1| 8| 3| 3| 3| 3| 3| 7| 9| 3| 3| 3| 3| 3| 3| 3| 6| 1| 3| 3| 3| 3| 3|            |
                                           | 3| 6| 1| 3| 9| 6| 6| 6| 6| 2| 4| 9| 6| 6| 6| 6| 6| 6| 7| 5| 6| 6| 6| 6| 6|            |
 __________________________________________|__________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|     A      |
    500 PPM                                | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|     L      |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 ENDOCRINE SYSTEM - cont                   |                                                                          |            |
                                           |                                                                          |            |
   Pituitary Gland                         | +  +  +  +  I  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Pars Distalis, Adenoma               |                                     X  X           X     X     X     X   |         13 |
                                           |__________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Follicular Cell, Adenoma             |                X                                                         |          4 |
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
    None                                   |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Clitoral Gland                          | +  +  M  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +|  46        |
                                           |__________________________________________________________________________|____________|
   Ovary                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Cystadenoma                          |                            X                                             |          3 |
      Granulosa Cell Tumor Benign          |                                              X                           |          2 |
      Hemangioma                           |                                                                          |          1 |
      Histiocytic Sarcoma                  | X                    X                    X                              |          3 |
      Lymphoma Malignant                   |                                                                          |          3 |
                                           |__________________________________________________________________________|____________|
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Histiocytic Sarcoma                  | X                    X                                                   |          2 |
      Lymphoma Malignant                   |                                                                          |          1 |
      Polyp Stromal                        |                X                                                         |          1 |
                                           |__________________________________________________________________________|____________|
   Vagina                                  |                   +                                                      |   1        |
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Histiocytic Sarcoma                  |                      X                    X                              |          2 |
      Lymphoma Malignant                   |                                                                          |          1 |
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                                                                                                    
                                                                                                                                    
                                                             Page  21                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 6| 7| 6| 4| 6| 7| 7| 7| 7| 5| 5| 6| 7| 7| 7| 7| 7| 7| 5| 6| 7| 7| 7| 7| 7|            |
                             DAY ON TEST   | 5| 3| 1| 8| 3| 3| 3| 3| 3| 7| 9| 3| 3| 3| 3| 3| 3| 3| 6| 1| 3| 3| 3| 3| 3|            |
                                           | 3| 6| 1| 3| 9| 6| 6| 6| 6| 2| 4| 9| 6| 6| 6| 6| 6| 6| 7| 5| 6| 6| 6| 6| 6|            |
 __________________________________________|__________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|     A      |
    500 PPM                                | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|     L      |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |            |
                                           |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Lymph Node                              |                                           +              +               |   2        |
      Iliac, Histiocytic Sarcoma           |                                                          X               |          1 |
      Renal, Histiocytic Sarcoma           |                                           X              X               |          2 |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Bronchial                   | M  +  +  M  M  +  M  M  +  +  +  +  +  +  +  M  M  +  +  M  M  +  M  M  M|  33        |
      Histiocytic Sarcoma                  |                                           X                              |          1 |
      Lymphoma Malignant                   |                                        X                                 |          4 |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | +  +  +  M  M  +  +  +  +  +  +  +  M  +  +  +  M  +  M  M  +  +  +  +  +|  42        |
      Histiocytic Sarcoma                  |                      X                    X                              |          2 |
      Lymphoma Malignant                   |                                                                          |          3 |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
      Histiocytic Sarcoma                  |                      X                    X              X               |          3 |
      Lymphoma Malignant                   |                   X                    X     X                           |          6 |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mediastinal                 | M  M  M  +  M  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +|  42        |
      Histiocytic Sarcoma                  |                                           X              X               |          2 |
      Lymphoma Malignant                   |                                                                          |          3 |
                                           |__________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Histiocytic Sarcoma                  |                                           X              X               |          2 |
      Lymphoma Malignant                   |                                        X        X                        |          7 |
                                           |__________________________________________________________________________|____________|
   Thymus                                  | M  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +|  44        |
      Lymphoma Malignant                   |                                                                          |          2 |
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +|  49        |
                                           |__________________________________________________________________________|____________|
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                                                                                                    
                                                                                                                                    
                                                             Page  22                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 6| 7| 6| 4| 6| 7| 7| 7| 7| 5| 5| 6| 7| 7| 7| 7| 7| 7| 5| 6| 7| 7| 7| 7| 7|            |
                             DAY ON TEST   | 5| 3| 1| 8| 3| 3| 3| 3| 3| 7| 9| 3| 3| 3| 3| 3| 3| 3| 6| 1| 3| 3| 3| 3| 3|            |
                                           | 3| 6| 1| 3| 9| 6| 6| 6| 6| 2| 4| 9| 6| 6| 6| 6| 6| 6| 7| 5| 6| 6| 6| 6| 6|            |
 __________________________________________|__________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|     A      |
    500 PPM                                | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|     L      |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 INTEGUMENTARY SYSTEM - cont               |                                                                          |            |
                                           |                                                                          |            |
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Subcutaneous Tissue, Fibrosarcoma    |                                     X                                    |          2 |
      Subcutaneous Tissue, Fibrous         |                                                                          |            |
          Histiocytoma                     |                                                                          |          1 |
      Subcutaneous Tissue, Hemangiosarcoma |                X                                                         |          1 |
      Subcutaneous Tissue, Sarcoma         |             X                                                            |          2 |
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Lymphoma Malignant                   |                                                                          |          1 |
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Larynx                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Alveolar/Bronchiolar Adenoma         |    X                                                                     |          2 |
      Alveolar/Bronchiolar Carcinoma       |                                  X                 X                     |          2 |
      Alveolar/Bronchiolar Carcinoma,      |                                                                          |            |
          Metastatic, Lung                 |                                  X                                       |          1 |
      Hepatoblastoma, Metastatic, Liver    |                                                                          |          1 |
      Hepatocellular Carcinoma, Metastatic,|                                                                          |            |
           Liver                           |                                                       X                 X|          4 |
      Histiocytic Sarcoma                  | X                    X                    X              X               |          4 |
      Lymphoma Malignant                   |                                                                          |          3 |
      Sarcoma, Metastatic, Skin            |             X                                                            |          1 |
                                           |__________________________________________________________________________|____________|
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                                                                                                    
                                                                                                                                    
                                                             Page  23                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 6| 7| 6| 4| 6| 7| 7| 7| 7| 5| 5| 6| 7| 7| 7| 7| 7| 7| 5| 6| 7| 7| 7| 7| 7|            |
                             DAY ON TEST   | 5| 3| 1| 8| 3| 3| 3| 3| 3| 7| 9| 3| 3| 3| 3| 3| 3| 3| 6| 1| 3| 3| 3| 3| 3|            |
                                           | 3| 6| 1| 3| 9| 6| 6| 6| 6| 2| 4| 9| 6| 6| 6| 6| 6| 6| 7| 5| 6| 6| 6| 6| 6|            |
 __________________________________________|__________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|     A      |
    500 PPM                                | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|     L      |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 RESPIRATORY SYSTEM - cont                 |                                                                          |            |
                                           |                                                                          |            |
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Lymphoma Malignant                   |                                                                          |          1 |
                                           |__________________________________________________________________________|____________|
   Pleura                                  |                                                                          |   1        |
      Hepatoblastoma, Metastatic, Liver    |                                                                          |          1 |
                                           |__________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Eye                                     |                                           +                              |   1        |
                                           |__________________________________________________________________________|____________|
   Harderian Gland                         |    +                                      +                              |   2        |
      Adenoma                              |    X                                                                     |          1 |
      Carcinoma                            |                                           X                              |          1 |
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Histiocytic Sarcoma                  |                      X                    X              X               |          3 |
      Lymphoma Malignant                   |                                                                          |          3 |
                                           |__________________________________________________________________________|____________|
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Histiocytic Sarcoma                  | X                                                                        |          1 |
      Lymphoma Malignant                   |                                                                          |          2 |
 __________________________________________________________________________________________________________________________________ 
 SYSTEMIC LESIONS                          |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Histiocytic Sarcoma                  | X                    X                    X              X               |          4 |
      Lymphoma Malignant                   |                   X                    X     X  X                        |          9 |
 __________________________________________________________________________________________________________________________________ 
                                                                                                                                    
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  24                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 7| 7| 7| 7| 5| 7| 7| 7| 7| 4| 7| 7| 7| 7| 7| 7| 7| 6| 7| 5| 7| 7|             
                             DAY ON TEST   | 3| 3| 3| 3| 3| 3| 3| 4| 3| 3| 3| 3| 7| 3| 3| 3| 3| 3| 3| 3| 2| 3| 0| 3| 3|             
                                           | 5| 5| 5| 5| 5| 5| 5| 3| 5| 5| 5| 5| 7| 5| 5| 5| 5| 5| 5| 6| 0| 6| 9| 6| 6|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5|             
    2000 PPM                               | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 ALIMENTARY SYSTEM                         |                                                                          |             
                                           |__________________________________________________________________________|             
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Gallbladder                             | +  +  +  +  +  +  +  A  +  +  +  +  +  M  +  +  +  +  +  +  +  M  +  M  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                                                                          |             
                                           |__________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                                                                          |             
                                           |__________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                                  X                                       |             
                                           |__________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hepatocellular Carcinoma             |       X           X              X                          X            |             
      Hepatocellular Carcinoma, Multiple   |                                                                          |             
      Hepatocellular Adenoma               |                X     X        X  X              X  X     X               |             
      Hepatocellular Adenoma, Multiple     |       X           X        X                                         X   |             
      Lymphoma Malignant                   |             X        X           X                          X            |             
                                           |__________________________________________________________________________|             
   Mesentery                               |                                              +           +               |             
      Lipoma                               |                                                                          |             
      Lymphoma Malignant                   |                                                                          |             
                                           |__________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                                                                X         |             
                                           |__________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |    X                                                                     |             
                                           |__________________________________________________________________________|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  25                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 7| 7| 7| 7| 5| 7| 7| 7| 7| 4| 7| 7| 7| 7| 7| 7| 7| 6| 7| 5| 7| 7|             
                             DAY ON TEST   | 3| 3| 3| 3| 3| 3| 3| 4| 3| 3| 3| 3| 7| 3| 3| 3| 3| 3| 3| 3| 2| 3| 0| 3| 3|             
                                           | 5| 5| 5| 5| 5| 5| 5| 3| 5| 5| 5| 5| 7| 5| 5| 5| 5| 5| 5| 6| 0| 6| 9| 6| 6|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5|             
    2000 PPM                               | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 ALIMENTARY SYSTEM - cont                  |                                                                          |             
                                           |                                                                          |             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                                                                          |             
      Squamous Cell Carcinoma              |          X                                                               |             
                                           |__________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                                                                          |             
      Squamous Cell Carcinoma, Metastatic, |                                                                          |             
           Stomach, Forestomach            |          X                                                               |             
                                           |__________________________________________________________________________|             
   Tooth                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                                                                X         |             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |__________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hepatocellular Carcinoma, Metastatic,|                                                                          |             
           Liver                           |                   X                                                      |             
                                           |__________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Pheochromocytoma Benign              |                                                                          |             
                                           |__________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Adenoma                              |                                                                          |             
                                           |__________________________________________________________________________|             
   Parathyroid Gland                       | +  +  +  M  +  M  +  A  +  +  +  +  +  +  M  +  +  +  +  +  +  M  +  M  +|             
                                           |__________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                                                                X         |             
      Pars Distalis, Adenoma               |          X  X  X              X              X           X     X         |             
      Pars Distalis, Carcinoma             |                                     X                                    |             
      Pars Intermedia, Adenoma             |                         X                                                |             
                                           |__________________________________________________________________________|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  26                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 7| 7| 7| 7| 5| 7| 7| 7| 7| 4| 7| 7| 7| 7| 7| 7| 7| 6| 7| 5| 7| 7|             
                             DAY ON TEST   | 3| 3| 3| 3| 3| 3| 3| 4| 3| 3| 3| 3| 7| 3| 3| 3| 3| 3| 3| 3| 2| 3| 0| 3| 3|             
                                           | 5| 5| 5| 5| 5| 5| 5| 3| 5| 5| 5| 5| 7| 5| 5| 5| 5| 5| 5| 6| 0| 6| 9| 6| 6|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5|             
    2000 PPM                               | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 ENDOCRINE SYSTEM - cont                   |                                                                          |             
                                           |                                                                          |             
   Thyroid Gland                           | +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Follicular Cell, Adenoma             |          X                 X              X                              |             
      Follicular Cell, Carcinoma           |                               X                                          |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Clitoral Gland                          | +  +  +  +  +  +  +  A  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Ovary                                   | +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cystadenoma                          |                                                                X         |             
      Hemangioma                           |                                  X                                       |             
      Hemangiosarcoma                      |                                                                          |             
      Histiocytic Sarcoma                  |                                                                          |             
      Luteoma                              |                                                                          |             
      Lymphoma Malignant                   |    X                             X                          X  X     X   |             
                                           |__________________________________________________________________________|             
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Histiocytic Sarcoma                  |                   X                                                      |             
      Lymphoma Malignant                   |                                                                          |             
      Polyp Stromal                        |                            X                                             |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Lymph Node                              |                                  +                                       |             
      Lymphoma Malignant                   |                                                                          |             
      Iliac, Lymphoma Malignant            |                                  X                                       |             
      Inguinal, Hemangiosarcoma            |                                                                          |             
      Pancreatic, Lymphoma Malignant       |                                  X                                       |             
      Renal, Lymphoma Malignant            |                                  X                                       |             
                                           |__________________________________________________________________________|             
   Lymph Node, Bronchial                   | M  +  +  M  +  M  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  M  M  +  +|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  27                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 7| 7| 7| 7| 5| 7| 7| 7| 7| 4| 7| 7| 7| 7| 7| 7| 7| 6| 7| 5| 7| 7|             
                             DAY ON TEST   | 3| 3| 3| 3| 3| 3| 3| 4| 3| 3| 3| 3| 7| 3| 3| 3| 3| 3| 3| 3| 2| 3| 0| 3| 3|             
                                           | 5| 5| 5| 5| 5| 5| 5| 3| 5| 5| 5| 5| 7| 5| 5| 5| 5| 5| 5| 6| 0| 6| 9| 6| 6|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5|             
    2000 PPM                               | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |             
                                           |                                                                          |             
      Lymphoma Malignant                   |    X                             X     X                    X        X   |             
                                           |__________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  +  +  +  +  M  A  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |    X                             X                          X  X        X|             
                                           |__________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  A  +  +  +  +  M  +  +  +  +  +  +  +  I  +  +  +  +|             
      Lymphoma Malignant                   |                                  X                             X        X|             
                                           |__________________________________________________________________________|             
   Lymph Node, Mediastinal                 | M  +  M  +  M  +  +  M  +  +  +  +  +  +  M  +  +  +  +  +  +  +  M  +  +|             
      Lymphoma Malignant                   |    X                             X                          X  X     X   |             
                                           |__________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |    X        X        X           X     X                    X  X     X  X|             
                                           |__________________________________________________________________________|             
   Thymus                                  | +  +  +  +  +  +  +  A  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |    X        X                    X                             X         |             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |__________________________________________________________________________|             
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Carcinoma                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Subcutaneous Tissue, Fibrosarcoma    |                                                                          |             
      Subcutaneous Tissue, Hemangiosarcoma |                               X                                          |             
      Subcutaneous Tissue, Lymphoma        |                                                                          |             
          Malignant                        |                                                             X            |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Carcinoma, Metastatic, Pituitary     |                                                                          |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  28                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 7| 7| 7| 7| 5| 7| 7| 7| 7| 4| 7| 7| 7| 7| 7| 7| 7| 6| 7| 5| 7| 7|             
                             DAY ON TEST   | 3| 3| 3| 3| 3| 3| 3| 4| 3| 3| 3| 3| 7| 3| 3| 3| 3| 3| 3| 3| 2| 3| 0| 3| 3|             
                                           | 5| 5| 5| 5| 5| 5| 5| 3| 5| 5| 5| 5| 7| 5| 5| 5| 5| 5| 5| 6| 0| 6| 9| 6| 6|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5|             
    2000 PPM                               | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 NERVOUS SYSTEM - cont                     |                                                                          |             
                                           |                                                                          |             
          Gland                            |                                     X                                    |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |__________________________________________________________________________|             
   Larynx                                  | +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Alveolar/Bronchiolar Adenoma         | X                                                     X                  |             
      Alveolar/Bronchiolar Carcinoma       |       X     X                                                            |             
      Hepatocellular Carcinoma, Metastatic,|                                                                          |             
           Liver                           |                   X                                                      |             
      Lymphoma Malignant                   |    X                 X           X                          X            |             
                                           |__________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Harderian Gland                         |    +                                                                     |             
      Adenoma                              |    X                                                                     |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                                  X                          X  X         |             
                                           |__________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                                                                X         |             
 __________________________________________|__________________________________________________________________________|             
 SYSTEMIC LESIONS                          |                                                                          |             
                                            __________________________________________________________________________|             
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Histiocytic Sarcoma                  |                   X                                                      |             
      Lymphoma Malignant                   |    X        X        X           X     X                    X  X     X  X|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  29                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 6| 7| 7| 7| 7| 7| 7| 7| 6| 6| 7| 7| 7| 7| 7| 6| 7| 7| 7| 6| 7| 7| 7| 6| 7|            |
                             DAY ON TEST   | 1| 3| 3| 3| 3| 3| 3| 3| 9| 2| 0| 3| 3| 3| 3| 7| 3| 3| 3| 8| 3| 3| 3| 0| 3|            |
                                           | 8| 6| 6| 6| 6| 6| 6| 6| 2| 8| 9| 6| 6| 6| 6| 5| 6| 6| 6| 6| 6| 6| 6| 0| 6|            |
 __________________________________________|__________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5|     A      |
    2000 PPM                               | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|     L      |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 ALIMENTARY SYSTEM                         |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Gallbladder                             | +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  A  +  +  +  A  +|  43        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Lymphoma Malignant                   |                                                          X               |          1 |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Rectum                 | I  +  +  +  +  I  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  47        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +|  47        |
      Lymphoma Malignant                   |                                                          X               |          1 |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  A  +  +  +  A  +|  46        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  A  +  +  +  A  +|  46        |
      Lymphoma Malignant                   |                                           X                              |          2 |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  A  +  +  +  A  +|  46        |
                                           |__________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hepatocellular Carcinoma             |                X                       X                                 |          6 |
      Hepatocellular Carcinoma, Multiple   |                                                                      X   |          1 |
      Hepatocellular Adenoma               |                                        X  X  X                 X         |         11 |
      Hepatocellular Adenoma, Multiple     |                                  X  X                 X           X      |          8 |
      Lymphoma Malignant                   |                               X              X           X               |          7 |
                                           |__________________________________________________________________________|____________|
   Mesentery                               |    +                             +     +  +           +  +               |   8        |
      Lipoma                               |                                  X                                       |          1 |
      Lymphoma Malignant                   |                                                          X               |          1 |
                                           |__________________________________________________________________________|____________|
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +|  48        |
      Lymphoma Malignant                   |                                                             X            |          2 |
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                                                                                                    
                                                                                                                                    
                                                             Page  30                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 6| 7| 7| 7| 7| 7| 7| 7| 6| 6| 7| 7| 7| 7| 7| 6| 7| 7| 7| 6| 7| 7| 7| 6| 7|            |
                             DAY ON TEST   | 1| 3| 3| 3| 3| 3| 3| 3| 9| 2| 0| 3| 3| 3| 3| 7| 3| 3| 3| 8| 3| 3| 3| 0| 3|            |
                                           | 8| 6| 6| 6| 6| 6| 6| 6| 2| 8| 9| 6| 6| 6| 6| 5| 6| 6| 6| 6| 6| 6| 6| 0| 6|            |
 __________________________________________|__________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5|     A      |
    2000 PPM                               | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|     L      |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 ALIMENTARY SYSTEM - cont                  |                                                                          |            |
                                           |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Lymphoma Malignant                   |                                                                          |          1 |
                                           |__________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Lymphoma Malignant                   |                                                          X               |          1 |
      Squamous Cell Carcinoma              |                                                                          |          1 |
                                           |__________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +|  48        |
      Lymphoma Malignant                   |                                                          X               |          1 |
      Squamous Cell Carcinoma, Metastatic, |                                                                          |            |
           Stomach, Forestomach            |                                                                          |          1 |
                                           |__________________________________________________________________________|____________|
   Tooth                                   |          +                                                               |   1        |
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Lymphoma Malignant                   |                                              X                           |          2 |
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Hepatocellular Carcinoma, Metastatic,|                                                                          |            |
           Liver                           |                                                                          |          1 |
                                           |__________________________________________________________________________|____________|
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Pheochromocytoma Benign              |          X     X                                                         |          2 |
                                           |__________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +|  48        |
      Adenoma                              |                                           X                              |          1 |
                                           |__________________________________________________________________________|____________|
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                                                                                                    
                                                                                                                                    
                                                             Page  31                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 6| 7| 7| 7| 7| 7| 7| 7| 6| 6| 7| 7| 7| 7| 7| 6| 7| 7| 7| 6| 7| 7| 7| 6| 7|            |
                             DAY ON TEST   | 1| 3| 3| 3| 3| 3| 3| 3| 9| 2| 0| 3| 3| 3| 3| 7| 3| 3| 3| 8| 3| 3| 3| 0| 3|            |
                                           | 8| 6| 6| 6| 6| 6| 6| 6| 2| 8| 9| 6| 6| 6| 6| 5| 6| 6| 6| 6| 6| 6| 6| 0| 6|            |
 __________________________________________|__________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5|     A      |
    2000 PPM                               | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|     L      |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 ENDOCRINE SYSTEM - cont                   |                                                                          |            |
                                           |                                                                          |            |
   Parathyroid Gland                       | +  +  M  +  +  M  +  +  +  +  M  +  +  +  +  M  M  +  +  M  +  +  +  M  +|  37        |
                                           |__________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +|  49        |
      Lymphoma Malignant                   |                                                                          |          1 |
      Pars Distalis, Adenoma               |          X           X        X                             X  X         |         12 |
      Pars Distalis, Carcinoma             |                                                                          |          1 |
      Pars Intermedia, Adenoma             |                                                                          |          1 |
                                           |__________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Follicular Cell, Adenoma             |                                                                          |          3 |
      Follicular Cell, Carcinoma           |                                                                          |          1 |
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
    None                                   |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Clitoral Gland                          | +  +  +  +  +  +  +  +  M  M  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +|  45        |
                                           |__________________________________________________________________________|____________|
   Ovary                                   | +  +  +  +  +  I  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
      Cystadenoma                          |                                                                          |          1 |
      Hemangioma                           |                                                                          |          1 |
      Hemangiosarcoma                      | X                                                                        |          1 |
      Histiocytic Sarcoma                  |                            X                                             |          1 |
      Luteoma                              |                                              X                           |          1 |
      Lymphoma Malignant                   |                               X                          X               |          7 |
                                           |__________________________________________________________________________|____________|
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Histiocytic Sarcoma                  |                                                                          |          1 |
      Lymphoma Malignant                   |                                                          X               |          1 |
      Polyp Stromal                        |                                                                          |          1 |
 _____________________________________________________________________________________________________________________|            |
                                                                                                                                    
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                                                                                                    
                                                                                                                                    
                                                             Page  32                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 6| 7| 7| 7| 7| 7| 7| 7| 6| 6| 7| 7| 7| 7| 7| 6| 7| 7| 7| 6| 7| 7| 7| 6| 7|            |
                             DAY ON TEST   | 1| 3| 3| 3| 3| 3| 3| 3| 9| 2| 0| 3| 3| 3| 3| 7| 3| 3| 3| 8| 3| 3| 3| 0| 3|            |
                                           | 8| 6| 6| 6| 6| 6| 6| 6| 2| 8| 9| 6| 6| 6| 6| 5| 6| 6| 6| 6| 6| 6| 6| 0| 6|            |
 __________________________________________|__________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5|     A      |
    2000 PPM                               | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|     L      |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                           |__________________________________________________________________________|____________|
   Lymph Node                              |    +                          +                       +  +               |   5        |
      Lymphoma Malignant                   |                               X                                          |          1 |
      Iliac, Lymphoma Malignant            |                               X                                          |          2 |
      Inguinal, Hemangiosarcoma            |    X                                                                     |          1 |
      Pancreatic, Lymphoma Malignant       |                               X                                          |          2 |
      Renal, Lymphoma Malignant            |                               X                       X  X               |          4 |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Bronchial                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  44        |
      Lymphoma Malignant                   |                               X              X        X  X  X            |         10 |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | +  +  +  M  +  +  +  +  +  +  +  +  M  +  +  M  +  +  +  +  +  +  +  +  +|  44        |
      Lymphoma Malignant                   |                               X                          X  X            |          8 |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  47        |
      Lymphoma Malignant                   |    X                          X           X              X  X            |          8 |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mediastinal                 | M  +  +  +  M  M  M  +  +  M  +  +  +  +  +  +  +  M  +  +  M  +  +  +  M|  36        |
      Lymphoma Malignant                   |                               X              X           X               |          8 |
                                           |__________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Lymphoma Malignant                   |    X                          X              X        X  X  X     X      |         16 |
                                           |__________________________________________________________________________|____________|
   Thymus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
      Lymphoma Malignant                   |                               X                          X               |          6 |
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +|  49        |
      Carcinoma                            |       X              X                                                   |          2 |
                                           |__________________________________________________________________________|____________|
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                                                                                                    
                                                                                                                                    
                                                             Page  33                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 6| 7| 7| 7| 7| 7| 7| 7| 6| 6| 7| 7| 7| 7| 7| 6| 7| 7| 7| 6| 7| 7| 7| 6| 7|            |
                             DAY ON TEST   | 1| 3| 3| 3| 3| 3| 3| 3| 9| 2| 0| 3| 3| 3| 3| 7| 3| 3| 3| 8| 3| 3| 3| 0| 3|            |
                                           | 8| 6| 6| 6| 6| 6| 6| 6| 2| 8| 9| 6| 6| 6| 6| 5| 6| 6| 6| 6| 6| 6| 6| 0| 6|            |
 __________________________________________|__________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5|     A      |
    2000 PPM                               | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|     L      |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 INTEGUMENTARY SYSTEM - cont               |                                                                          |            |
                                           |                                                                          |            |
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +|  49        |
      Subcutaneous Tissue, Fibrosarcoma    |                         X                                                |          1 |
      Subcutaneous Tissue, Hemangiosarcoma |                                                                          |          1 |
      Subcutaneous Tissue, Lymphoma        |                                                                          |            |
          Malignant                        |                                                                          |          1 |
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Carcinoma, Metastatic, Pituitary     |                                                                          |            |
          Gland                            |                                                                          |          1 |
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Larynx                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                           |__________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Alveolar/Bronchiolar Adenoma         |                                                                          |          2 |
      Alveolar/Bronchiolar Carcinoma       |                                                                          |          2 |
      Hepatocellular Carcinoma, Metastatic,|                                                                          |            |
           Liver                           |                X                                                         |          2 |
      Lymphoma Malignant                   |                                              X           X               |          6 |
                                           |__________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                           |__________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                                                                                                    
                                                                                                                                    
                                                             Page  34                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 6| 7| 7| 7| 7| 7| 7| 7| 6| 6| 7| 7| 7| 7| 7| 6| 7| 7| 7| 6| 7| 7| 7| 6| 7|            |
                             DAY ON TEST   | 1| 3| 3| 3| 3| 3| 3| 3| 9| 2| 0| 3| 3| 3| 3| 7| 3| 3| 3| 8| 3| 3| 3| 0| 3|            |
                                           | 8| 6| 6| 6| 6| 6| 6| 6| 2| 8| 9| 6| 6| 6| 6| 5| 6| 6| 6| 6| 6| 6| 6| 0| 6|            |
 __________________________________________|__________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5|     A      |
    2000 PPM                               | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|     L      |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 SPECIAL SENSES SYSTEM - cont              |                                                                          |            |
                                           |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Harderian Gland                         |                                                                          |   1        |
      Adenoma                              |                                                                          |          1 |
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Lymphoma Malignant                   |                                                          X  X            |          5 |
                                           |__________________________________________________________________________|____________|
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Lymphoma Malignant                   |                                                          X               |          2 |
 __________________________________________________________________________________________________________________________________ 
 SYSTEMIC LESIONS                          |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Histiocytic Sarcoma                  |                            X                                             |          2 |
      Lymphoma Malignant                   |    X                          X           X  X        X  X  X     X      |         17 |
 __________________________________________________________________________________________________________________________________ 
                                                                                                                                    
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  35                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 5| 7| 6| 7| 7| 7| 6| 7| 7| 7| 7| 5| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7|             
                             DAY ON TEST   | 6| 3| 5| 3| 3| 3| 7| 2| 3| 0| 2| 8| 3| 3| 3| 1| 3| 3| 2| 3| 3| 3| 3| 3| 3|             
                                           | 5| 5| 3| 5| 5| 5| 2| 9| 5| 1| 1| 3| 5| 5| 5| 5| 5| 5| 1| 5| 5| 5| 5| 5| 5|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7|             
    8000 PPM                               | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 ALIMENTARY SYSTEM                         |                                                                          |             
                                           |__________________________________________________________________________|             
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Gallbladder                             | A  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  A  +  +  +  M  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Cecum                  | A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Small, Duodenum               | A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Small, Jejunum                | A  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +|             
      Lymphoma Malignant                   |    X                                   X                                 |             
                                           |__________________________________________________________________________|             
   Intestine Small, Ileum                  | A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                                                                X         |             
                                           |__________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hepatocellular Carcinoma             |       X                    X  X                    X                     |             
      Hepatocellular Carcinoma, Multiple   |                                                             X            |             
      Hepatocellular Adenoma               |             X        X              X                          X  X      |             
      Hepatocellular Adenoma, Multiple     |          X                 X                                X            |             
      Lymphoma Malignant                   |             X                 X  X           X                           |             
                                           |__________________________________________________________________________|             
   Mesentery                               |       +  +        +     +                                   +        +   |             
                                           |__________________________________________________________________________|             
   Pancreas                                | A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |    X                          X                                          |             
                                           |__________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                               X     X                                    |             
                                           |__________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                               X                                          |             
                                           |__________________________________________________________________________|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  36                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 5| 7| 6| 7| 7| 7| 6| 7| 7| 7| 7| 5| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7|             
                             DAY ON TEST   | 6| 3| 5| 3| 3| 3| 7| 2| 3| 0| 2| 8| 3| 3| 3| 1| 3| 3| 2| 3| 3| 3| 3| 3| 3|             
                                           | 5| 5| 3| 5| 5| 5| 2| 9| 5| 1| 1| 3| 5| 5| 5| 5| 5| 5| 1| 5| 5| 5| 5| 5| 5|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7|             
    8000 PPM                               | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 ALIMENTARY SYSTEM - cont                  |                                                                          |             
                                           |                                                                          |             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                               X                                          |             
                                           |__________________________________________________________________________|             
   Tongue                                  |                                                                          |             
      Squamous Cell Papilloma              |                                                                          |             
                                           |__________________________________________________________________________|             
   Tooth                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                               X                                          |             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |__________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Capsule, Adenoma                     |                                                 X                        |             
                                           |__________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  I  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Pheochromocytoma Benign              |    X                                                                     |             
      Bilateral, Pheochromocytoma Malignant|          X                                                               |             
                                           |__________________________________________________________________________|             
   Islets, Pancreatic                      | A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Parathyroid Gland                       | +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  M  +|             
                                           |__________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                                                                          |             
      Pars Distalis, Adenoma               |    X              X     X  X                       X                    X|             
                                           |__________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                                                                          |             
      Follicular Cell, Adenoma             |                         X                                                |             
      Follicular Cell, Adenoma, Multiple   |                                                    X                     |             
      Follicular Cell, Carcinoma           |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
    None                                   |                                                                          |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                             Page  37                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 5| 7| 6| 7| 7| 7| 6| 7| 7| 7| 7| 5| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7|             
                             DAY ON TEST   | 6| 3| 5| 3| 3| 3| 7| 2| 3| 0| 2| 8| 3| 3| 3| 1| 3| 3| 2| 3| 3| 3| 3| 3| 3|             
                                           | 5| 5| 3| 5| 5| 5| 2| 9| 5| 1| 1| 3| 5| 5| 5| 5| 5| 5| 1| 5| 5| 5| 5| 5| 5|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7|             
    8000 PPM                               | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Clitoral Gland                          | +  +  M  M  +  +  +  +  +  +  M  M  +  +  +  +  +  +  +  +  +  M  +  +  +|             
                                           |__________________________________________________________________________|             
   Ovary                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cystadenoma                          |                                                          X              X|             
      Granulosa-Theca Tumor Benign         |                                                                          |             
      Lymphoma Malignant                   |                               X  X  X                                    |             
                                           |__________________________________________________________________________|             
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                               X                                          |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                                  X                                       |             
                                           |__________________________________________________________________________|             
   Lymph Node                              |                               +  +           +                           |             
      Lymphoma Malignant                   |                                              X                           |             
      Iliac, Lymphoma Malignant            |                                              X                           |             
      Pancreatic, Lymphoma Malignant       |                                  X                                       |             
      Renal, Lymphoma Malignant            |                               X  X           X                           |             
                                           |__________________________________________________________________________|             
   Lymph Node, Bronchial                   | +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +|             
      Lymphoma Malignant                   |    X                          X  X     X     X                           |             
                                           |__________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  M  +  +  +  +  +  M  M  +  +  M  +  +  +  +  +  +  +  M  +  +  +  +|             
      Lymphoma Malignant                   |    X                          X  X     X     X                           |             
                                           |__________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                               X  X  X  X     X                           |             
                                           |__________________________________________________________________________|             
   Lymph Node, Mediastinal                 | +  +  M  +  +  M  +  +  +  +  +  +  +  M  M  +  +  +  +  +  +  +  +  +  M|             
      Lymphoma Malignant                   |    X                          X  X  X        X                           |             
                                           |__________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemangiosarcoma                      |                X                                                         |             
      Lymphoma Malignant                   |    X        X                 X  X  X        X                 X         |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  38                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 5| 7| 6| 7| 7| 7| 6| 7| 7| 7| 7| 5| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7|             
                             DAY ON TEST   | 6| 3| 5| 3| 3| 3| 7| 2| 3| 0| 2| 8| 3| 3| 3| 1| 3| 3| 2| 3| 3| 3| 3| 3| 3|             
                                           | 5| 5| 3| 5| 5| 5| 2| 9| 5| 1| 1| 3| 5| 5| 5| 5| 5| 5| 1| 5| 5| 5| 5| 5| 5|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7|             
    8000 PPM                               | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |             
                                           |                                                                          |             
                                           |__________________________________________________________________________|             
   Thymus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  M  +|             
      Lymphoma Malignant                   |                               X  X  X  X     X                           |             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |__________________________________________________________________________|             
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Subcutaneous Tissue, Fibrosarcoma    |                      X                                                   |             
      Subcutaneous Tissue, Lymphoma        |                                                                          |             
          Malignant                        |                               X                                          |             
      Subcutaneous Tissue, Sarcoma         |                                        X                                 |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |__________________________________________________________________________|             
   Larynx                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Alveolar/Bronchiolar Adenoma         |                            X                                      X      |             
      Alveolar/Bronchiolar Carcinoma       |                                     X                                    |             
      Hepatocellular Carcinoma, Metastatic,|                                                                          |             
           Liver                           |                                                                          |             
      Lymphoma Malignant                   |    X                          X  X                                       |             
      Pheochromocytoma Malignant,          |                                                                          |             
          Metastatic, Adrenal Medulla      |          X                                                               |             
                                           |__________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  39                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 5| 7| 6| 7| 7| 7| 6| 7| 7| 7| 7| 5| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7|             
                             DAY ON TEST   | 6| 3| 5| 3| 3| 3| 7| 2| 3| 0| 2| 8| 3| 3| 3| 1| 3| 3| 2| 3| 3| 3| 3| 3| 3|             
                                           | 5| 5| 3| 5| 5| 5| 2| 9| 5| 1| 1| 3| 5| 5| 5| 5| 5| 5| 1| 5| 5| 5| 5| 5| 5|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7|             
    8000 PPM                               | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 RESPIRATORY SYSTEM - cont                 |                                                                          |             
                                           |                                                                          |             
                                           |__________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Eye                                     |                                              +                           |             
                                           |__________________________________________________________________________|             
   Harderian Gland                         |                                              +                           |             
      Adenoma                              |                                                                          |             
      Carcinoma                            |                                              X                           |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |    X                          X                                          |             
                                           |__________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                               X                                          |             
 __________________________________________|__________________________________________________________________________|             
 SYSTEMIC LESIONS                          |                                                                          |             
                                            __________________________________________________________________________|             
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |    X        X                 X  X  X  X     X                 X         |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  40                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 5| 5| 7| 7| 6| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7|            |
                             DAY ON TEST   | 3| 3| 9| 2| 3| 3| 4| 3| 3| 3| 0| 3| 8| 3| 3| 3| 0| 3| 1| 3| 3| 0| 3| 3| 3|            |
                                           | 6| 6| 6| 7| 6| 6| 5| 6| 6| 6| 9| 6| 7| 6| 6| 6| 3| 6| 7| 6| 6| 9| 6| 6| 6|            |
 __________________________________________|__________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7|     A      |
    8000 PPM                               | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|     L      |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 ALIMENTARY SYSTEM                         |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Gallbladder                             | +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +|  43        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Rectum                 | +  +  I  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  47        |
      Lymphoma Malignant                   |                                     X                       X            |          4 |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +|  47        |
      Lymphoma Malignant                   |                                                                          |          1 |
                                           |__________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hepatocellular Carcinoma             |       X  X        X                                   X                 X|          9 |
      Hepatocellular Carcinoma, Multiple   |                                           X                              |          2 |
      Hepatocellular Adenoma               |    X                    X        X                 X     X  X  X     X   |         13 |
      Hepatocellular Adenoma, Multiple     | X     X        X     X                                                   |          7 |
      Lymphoma Malignant                   |                X        X           X           X                        |          8 |
                                           |__________________________________________________________________________|____________|
   Mesentery                               |          +                       +                       +     +         |  10        |
                                           |__________________________________________________________________________|____________|
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Lymphoma Malignant                   |                         X           X           X                        |          5 |
                                           |__________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Lymphoma Malignant                   |                                                             X            |          3 |
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                                                                                                    
                                                                                                                                    
                                                             Page  41                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 5| 5| 7| 7| 6| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7|            |
                             DAY ON TEST   | 3| 3| 9| 2| 3| 3| 4| 3| 3| 3| 0| 3| 8| 3| 3| 3| 0| 3| 1| 3| 3| 0| 3| 3| 3|            |
                                           | 6| 6| 6| 7| 6| 6| 5| 6| 6| 6| 9| 6| 7| 6| 6| 6| 3| 6| 7| 6| 6| 9| 6| 6| 6|            |
 __________________________________________|__________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7|     A      |
    8000 PPM                               | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|     L      |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 ALIMENTARY SYSTEM - cont                  |                                                                          |            |
                                           |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Lymphoma Malignant                   |                                                                          |          1 |
                                           |__________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Lymphoma Malignant                   |                                                 X                        |          2 |
                                           |__________________________________________________________________________|____________|
   Tongue                                  |                                                                +         |   1        |
      Squamous Cell Papilloma              |                                                                X         |          1 |
                                           |__________________________________________________________________________|____________|
   Tooth                                   |       +                                                                  |   1        |
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Lymphoma Malignant                   |                                     X           X                        |          3 |
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Capsule, Adenoma                     |                                                                          |          1 |
                                           |__________________________________________________________________________|____________|
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Pheochromocytoma Benign              |                                                                         X|          2 |
      Bilateral, Pheochromocytoma Malignant|                                                                          |          1 |
                                           |__________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                           |__________________________________________________________________________|____________|
   Parathyroid Gland                       | +  M  +  +  +  +  +  M  +  +  M  +  +  M  +  +  M  +  M  +  M  +  +  +  +|  41        |
                                           |__________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +|  49        |
      Lymphoma Malignant                   |                                                 X                        |          1 |
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                                                                                                    
                                                                                                                                    
                                                             Page  42                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 5| 5| 7| 7| 6| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7|            |
                             DAY ON TEST   | 3| 3| 9| 2| 3| 3| 4| 3| 3| 3| 0| 3| 8| 3| 3| 3| 0| 3| 1| 3| 3| 0| 3| 3| 3|            |
                                           | 6| 6| 6| 7| 6| 6| 5| 6| 6| 6| 9| 6| 7| 6| 6| 6| 3| 6| 7| 6| 6| 9| 6| 6| 6|            |
 __________________________________________|__________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7|     A      |
    8000 PPM                               | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|     L      |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 ENDOCRINE SYSTEM - cont                   |                                                                          |            |
                                           |                                                                          |            |
      Pars Distalis, Adenoma               |                                  X     X  X     X  X           X         |         12 |
                                           |__________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Lymphoma Malignant                   |                                                 X                        |          1 |
      Follicular Cell, Adenoma             |                                                                          |          1 |
      Follicular Cell, Adenoma, Multiple   |                                                                          |          1 |
      Follicular Cell, Carcinoma           |                                           X                              |          1 |
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
    None                                   |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Clitoral Gland                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  45        |
                                           |__________________________________________________________________________|____________|
   Ovary                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Cystadenoma                          |                                                                          |          2 |
      Granulosa-Theca Tumor Benign         |                                                    X                     |          1 |
      Lymphoma Malignant                   |                                     X           X                        |          5 |
                                           |__________________________________________________________________________|____________|
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Lymphoma Malignant                   |                                     X                                    |          2 |
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Lymphoma Malignant                   |                                                                          |          1 |
                                           |__________________________________________________________________________|____________|
   Lymph Node                              |                                     +                                    |   4        |
      Lymphoma Malignant                   |                                                                          |          1 |
      Iliac, Lymphoma Malignant            |                                     X                                    |          2 |
      Pancreatic, Lymphoma Malignant       |                                     X                                    |          2 |
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                                                                                                    
                                                                                                                                    
                                                             Page  43                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 5| 5| 7| 7| 6| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7|            |
                             DAY ON TEST   | 3| 3| 9| 2| 3| 3| 4| 3| 3| 3| 0| 3| 8| 3| 3| 3| 0| 3| 1| 3| 3| 0| 3| 3| 3|            |
                                           | 6| 6| 6| 7| 6| 6| 5| 6| 6| 6| 9| 6| 7| 6| 6| 6| 3| 6| 7| 6| 6| 9| 6| 6| 6|            |
 __________________________________________|__________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7|     A      |
    8000 PPM                               | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|     L      |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |            |
                                           |                                                                          |            |
      Renal, Lymphoma Malignant            |                                                                          |          3 |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Bronchial                   | +  +  +  +  +  +  M  +  +  M  +  +  +  M  +  +  M  +  +  +  +  +  +  +  +|  44        |
      Lymphoma Malignant                   |                X        X           X                       X            |          9 |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | +  M  +  M  +  +  M  +  +  +  +  +  +  +  M  +  +  +  +  +  +  M  M  +  M|  38        |
      Lymphoma Malignant                   |                         X                       X           X            |          8 |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Lymphoma Malignant                   |                      X  X           X           X           X            |         10 |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mediastinal                 | +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  M  +  +  +  +  +  M  +|  42        |
      Lymphoma Malignant                   |                X                    X           X           X            |          9 |
                                           |__________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hemangiosarcoma                      |                                                                          |          1 |
      Lymphoma Malignant                   |                X        X           X           X  X        X     X  X  X|         16 |
                                           |__________________________________________________________________________|____________|
   Thymus                                  | +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  M  +  +  +  +|  46        |
      Lymphoma Malignant                   |                                     X     X     X                        |          8 |
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Subcutaneous Tissue, Fibrosarcoma    |                                                                          |          1 |
      Subcutaneous Tissue, Lymphoma        |                                                                          |            |
          Malignant                        |                                                                          |          1 |
      Subcutaneous Tissue, Sarcoma         |                               X                                          |          2 |
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                                                                                                    
                                                                                                                                    
                                                             Page  44                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 5| 5| 7| 7| 6| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7|            |
                             DAY ON TEST   | 3| 3| 9| 2| 3| 3| 4| 3| 3| 3| 0| 3| 8| 3| 3| 3| 0| 3| 1| 3| 3| 0| 3| 3| 3|            |
                                           | 6| 6| 6| 7| 6| 6| 5| 6| 6| 6| 9| 6| 7| 6| 6| 6| 3| 6| 7| 6| 6| 9| 6| 6| 6|            |
 __________________________________________|__________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7|     A      |
    8000 PPM                               | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|     L      |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 MUSCULOSKELETAL SYSTEM - cont             |                                                                          |            |
                                           |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Larynx                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Alveolar/Bronchiolar Adenoma         |                                                                          |          2 |
      Alveolar/Bronchiolar Carcinoma       |                                                                          |          1 |
      Hepatocellular Carcinoma, Metastatic,|                                                                          |            |
           Liver                           |          X                                                               |          1 |
      Lymphoma Malignant                   |                         X           X           X                        |          6 |
      Pheochromocytoma Malignant,          |                                                                          |            |
          Metastatic, Adrenal Medulla      |                                                                          |          1 |
                                           |__________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Eye                                     |                                                                          |   1        |
                                           |__________________________________________________________________________|____________|
   Harderian Gland                         |                            +                                             |   2        |
      Adenoma                              |                            X                                             |          1 |
      Carcinoma                            |                                                                          |          1 |
 _____________________________________________________________________________________________________________________|            |
                                                                                                                                    
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                                                                                                    
                                                                                                                                    
                                                             Page  45                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 5| 5| 7| 7| 6| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7|            |
                             DAY ON TEST   | 3| 3| 9| 2| 3| 3| 4| 3| 3| 3| 0| 3| 8| 3| 3| 3| 0| 3| 1| 3| 3| 0| 3| 3| 3|            |
                                           | 6| 6| 6| 7| 6| 6| 5| 6| 6| 6| 9| 6| 7| 6| 6| 6| 3| 6| 7| 6| 6| 9| 6| 6| 6|            |
 __________________________________________|__________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   B6C3F1 MICE FEMALE                      | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7|     A      |
    8000 PPM                               | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|     L      |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 URINARY SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Lymphoma Malignant                   |                                                 X                       X|          4 |
                                           |__________________________________________________________________________|____________|
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Lymphoma Malignant                   |                                     X           X                        |          3 |
 __________________________________________________________________________________________________________________________________ 
 SYSTEMIC LESIONS                          |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Lymphoma Malignant                   |                X     X  X           X     X     X  X        X     X  X  X|         19 |
 __________________________________________________________________________________________________________________________________ 
                                                                                                                                    
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  46                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 5| 4| 7| 7| 7| 7| 7| 6| 7| 7| 6| 7| 4| 6| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7|             
                             DAY ON TEST   | 3| 6| 8| 3| 3| 3| 3| 3| 1| 3| 3| 8| 3| 2| 6| 1| 9| 3| 3| 3| 3| 3| 0| 3| 3|             
                                           | 3| 0| 3| 3| 3| 3| 3| 3| 0| 3| 3| 1| 3| 6| 4| 5| 5| 3| 3| 3| 3| 3| 9| 3| 4|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
    CONTROL                                | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 ALIMENTARY SYSTEM                         |                                                                          |             
                                           |__________________________________________________________________________|             
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Gallbladder                             | +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  M  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Colon                  | +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Rectum                 | +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Cecum                  | +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Small, Duodenum               | +  A  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +|             
      Histiocytic Sarcoma                  |                                                                          |             
                                           |__________________________________________________________________________|             
   Intestine Small, Jejunum                | +  A  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Small, Ileum                  | +  A  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                                                    X                     |             
                                           |__________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemangiosarcoma                      |                                           X                              |             
      Hepatocellular Carcinoma             |    X  X                          X              X                 X      |             
      Hepatocellular Carcinoma, Multiple   |                                                                          |             
      Hepatocellular Adenoma               |             X              X  X           X     X              X  X  X   |             
      Hepatocellular Adenoma, Multiple     |                   X                                                      |             
      Lymphoma Malignant                   |                                                                   X      |             
                                           |__________________________________________________________________________|             
   Mesentery                               |                         +                    +        +                  |             
                                           |__________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Squamous Cell Papilloma              |                                                                          |             
                                           |__________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  47                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 5| 4| 7| 7| 7| 7| 7| 6| 7| 7| 6| 7| 4| 6| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7|             
                             DAY ON TEST   | 3| 6| 8| 3| 3| 3| 3| 3| 1| 3| 3| 8| 3| 2| 6| 1| 9| 3| 3| 3| 3| 3| 0| 3| 3|             
                                           | 3| 0| 3| 3| 3| 3| 3| 3| 0| 3| 3| 1| 3| 6| 4| 5| 5| 3| 3| 3| 3| 3| 9| 3| 4|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
    CONTROL                                | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 ALIMENTARY SYSTEM - cont                  |                                                                          |             
                                           |                                                                          |             
                                           |__________________________________________________________________________|             
   Tooth                                   | +                                   +              +           +         |             
      Odontoma                             |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |__________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Adenoma                              |                                     X                                    |             
      Capsule, Adenoma                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Parathyroid Gland                       | +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Preputial Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Prostate                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  I  +|             
                                           |__________________________________________________________________________|             
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  48                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 5| 4| 7| 7| 7| 7| 7| 6| 7| 7| 6| 7| 4| 6| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7|             
                             DAY ON TEST   | 3| 6| 8| 3| 3| 3| 3| 3| 1| 3| 3| 8| 3| 2| 6| 1| 9| 3| 3| 3| 3| 3| 0| 3| 3|             
                                           | 3| 0| 3| 3| 3| 3| 3| 3| 0| 3| 3| 1| 3| 6| 4| 5| 5| 3| 3| 3| 3| 3| 9| 3| 4|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
    CONTROL                                | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 GENITAL SYSTEM - cont                     |                                                                          |             
                                           |                                                                          |             
                                           |__________________________________________________________________________|             
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Lymph Node                              |                                                    +                     |             
      Iliac, Lymphoma Malignant            |                                                                          |             
      Pancreatic, Lymphoma Malignant       |                                                    X                     |             
      Renal, Histiocytic Sarcoma           |                                                                          |             
      Renal, Lymphoma Malignant            |                                                    X                     |             
                                           |__________________________________________________________________________|             
   Lymph Node, Bronchial                   | +  +  +  +  M  M  M  +  +  M  M  M  +  M  M  +  +  +  +  +  M  M  +  +  +|             
      Lymphoma Malignant                   |                                                                   X      |             
                                           |__________________________________________________________________________|             
   Lymph Node, Mandibular                  | M  +  +  M  +  +  +  M  +  +  +  +  +  +  M  +  M  M  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                                                                   X      |             
                                           |__________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +|             
      Histiocytic Sarcoma                  |                                                                          |             
      Lymphoma Malignant                   |                                                    X              X      |             
                                           |__________________________________________________________________________|             
   Lymph Node, Mediastinal                 | +  M  M  +  M  +  +  M  +  M  +  +  M  +  +  +  +  +  M  +  M  M  +  +  +|             
      Lymphoma Malignant                   |                                                                   X      |             
                                           |__________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Histiocytic Sarcoma                  |                                                                          |             
      Lymphoma Malignant                   |                                                    X              X      |             
                                           |__________________________________________________________________________|             
   Thymus                                  | +  +  +  +  +  +  +  M  +  +  +  +  +  +  M  +  M  +  +  +  +  +  M  M  M|             
      Lymphoma Malignant                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |__________________________________________________________________________|             
   Mammary Gland                           | M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  49                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 5| 4| 7| 7| 7| 7| 7| 6| 7| 7| 6| 7| 4| 6| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7|             
                             DAY ON TEST   | 3| 6| 8| 3| 3| 3| 3| 3| 1| 3| 3| 8| 3| 2| 6| 1| 9| 3| 3| 3| 3| 3| 0| 3| 3|             
                                           | 3| 0| 3| 3| 3| 3| 3| 3| 0| 3| 3| 1| 3| 6| 4| 5| 5| 3| 3| 3| 3| 3| 9| 3| 4|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
    CONTROL                                | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 INTEGUMENTARY SYSTEM - cont               |                                                                          |             
                                           |                                                                          |             
                                           |__________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  I  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |__________________________________________________________________________|             
   Larynx                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Alveolar/Bronchiolar Adenoma         | X                                   X                    X        X      |             
      Alveolar/Bronchiolar Adenoma,        |                                                                          |             
          Multiple                         |             X                                X                           |             
      Alveolar/Bronchiolar Carcinoma       |             X           X                                                |             
      Hepatocellular Carcinoma, Metastatic,|                                                                          |             
           Liver                           |                                  X              X                 X      |             
                                           |__________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Eye                                     |                         +                                            +   |             
                                           |__________________________________________________________________________|             
   Harderian Gland                         | +                       +                                                |             
      Adenoma                              | X                       X                                                |             
      Carcinoma                            |                                                                          |             
      Bilateral, Adenoma                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  50                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 5| 4| 7| 7| 7| 7| 7| 6| 7| 7| 6| 7| 4| 6| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7|             
                             DAY ON TEST   | 3| 6| 8| 3| 3| 3| 3| 3| 1| 3| 3| 8| 3| 2| 6| 1| 9| 3| 3| 3| 3| 3| 0| 3| 3|             
                                           | 3| 0| 3| 3| 3| 3| 3| 3| 0| 3| 3| 1| 3| 6| 4| 5| 5| 3| 3| 3| 3| 3| 9| 3| 4|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
    CONTROL                                | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                                                                   X      |             
      Renal Tubule, Adenoma                |                                                                          |             
                                           |__________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 __________________________________________|__________________________________________________________________________|             
 SYSTEMIC LESIONS                          |                                                                          |             
                                            __________________________________________________________________________|             
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Histiocytic Sarcoma                  |                                                                          |             
      Lymphoma Malignant                   |                                                    X              X      |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  51                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 5| 7| 6| 7| 7| 6| 5| 6| 6| 7| 7| 7| 7| 7| 3| 7| 7| 7| 5| 7| 7| 5| 6| 7| 3|            |
                             DAY ON TEST   | 2| 3| 5| 3| 3| 1| 8| 5| 0| 2| 3| 3| 0| 3| 8| 3| 3| 3| 9| 3| 3| 8| 9| 3| 9|            |
                                           | 7| 4| 3| 4| 4| 1| 0| 3| 8| 3| 4| 4| 8| 4| 7| 4| 4| 4| 2| 4| 4| 9| 5| 4| 9|            |
 __________________________________________|__________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     A      |
    CONTROL                                | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|     L      |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 ALIMENTARY SYSTEM                         |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Gallbladder                             | +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  M  +  +  +|  46        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  A  +  +  +|  47        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  A  +  +  +|  47        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  A  +  +  +|  47        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  A  +  +  +|  46        |
      Histiocytic Sarcoma                  |       X                                                                  |          1 |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  A  +  +  A  +  +  +|  45        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  A  +  +  +|  46        |
      Lymphoma Malignant                   |             X  X                                                         |          3 |
                                           |__________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hemangiosarcoma                      |                                                                          |          1 |
      Hepatocellular Carcinoma             |       X     X     X        X           X                       X        X|         12 |
      Hepatocellular Carcinoma, Multiple   |                         X                                                |          1 |
      Hepatocellular Adenoma               |          X                    X  X     X     X                    X  X   |         15 |
      Hepatocellular Adenoma, Multiple     |                      X                          X     X  X               |          5 |
      Lymphoma Malignant                   |                                                                          |          1 |
                                           |__________________________________________________________________________|____________|
   Mesentery                               |       +                                                                  |   4        |
                                           |__________________________________________________________________________|____________|
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                                                                                                    
                                                                                                                                    
                                                             Page  52                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 5| 7| 6| 7| 7| 6| 5| 6| 6| 7| 7| 7| 7| 7| 3| 7| 7| 7| 5| 7| 7| 5| 6| 7| 3|            |
                             DAY ON TEST   | 2| 3| 5| 3| 3| 1| 8| 5| 0| 2| 3| 3| 0| 3| 8| 3| 3| 3| 9| 3| 3| 8| 9| 3| 9|            |
                                           | 7| 4| 3| 4| 4| 1| 0| 3| 8| 3| 4| 4| 8| 4| 7| 4| 4| 4| 2| 4| 4| 9| 5| 4| 9|            |
 __________________________________________|__________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     A      |
    CONTROL                                | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|     L      |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 ALIMENTARY SYSTEM - cont                  |                                                                          |            |
                                           |                                                                          |            |
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Squamous Cell Papilloma              |                                                          X               |          1 |
                                           |__________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +|  49        |
                                           |__________________________________________________________________________|____________|
   Tooth                                   | +                                   +                 +                  |   7        |
      Odontoma                             | X                                                                        |          1 |
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +|  49        |
      Adenoma                              |                                                                          |          1 |
      Capsule, Adenoma                     |    X                                                                     |          1 |
                                           |__________________________________________________________________________|____________|
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +|  49        |
                                           |__________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Parathyroid Gland                       | +  I  +  +  +  M  +  M  M  +  +  M  M  +  +  +  +  +  M  +  +  M  +  +  +|  41        |
                                           |__________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
    None                                   |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                                                                                                    
                                                                                                                                    
                                                             Page  53                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 5| 7| 6| 7| 7| 6| 5| 6| 6| 7| 7| 7| 7| 7| 3| 7| 7| 7| 5| 7| 7| 5| 6| 7| 3|            |
                             DAY ON TEST   | 2| 3| 5| 3| 3| 1| 8| 5| 0| 2| 3| 3| 0| 3| 8| 3| 3| 3| 9| 3| 3| 8| 9| 3| 9|            |
                                           | 7| 4| 3| 4| 4| 1| 0| 3| 8| 3| 4| 4| 8| 4| 7| 4| 4| 4| 2| 4| 4| 9| 5| 4| 9|            |
 __________________________________________|__________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     A      |
    CONTROL                                | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|     L      |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 GENITAL SYSTEM - cont                     |                                                                          |            |
                                           |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Preputial Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Prostate                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +|  48        |
                                           |__________________________________________________________________________|____________|
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +|  49        |
                                           |__________________________________________________________________________|____________|
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Lymph Node                              |       +        +                       +                                 |   4        |
      Iliac, Lymphoma Malignant            |                X                                                         |          1 |
      Pancreatic, Lymphoma Malignant       |                                                                          |          1 |
      Renal, Histiocytic Sarcoma           |       X                                                                  |          1 |
      Renal, Lymphoma Malignant            |                X                                                         |          2 |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Bronchial                   | +  +  M  M  +  M  M  +  M  +  +  +  +  +  M  +  +  M  +  +  +  +  M  M  M|  30        |
      Lymphoma Malignant                   |                                                                          |          1 |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | M  +  M  +  +  +  +  M  +  +  M  M  +  +  +  M  M  M  +  +  +  M  M  +  +|  34        |
      Lymphoma Malignant                   |                X                                                         |          2 |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
      Histiocytic Sarcoma                  |       X                                                                  |          1 |
      Lymphoma Malignant                   |                X                                                         |          3 |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mediastinal                 | +  +  +  +  M  +  +  M  M  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +|  37        |
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                                                                                                    
                                                                                                                                    
                                                             Page  54                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 5| 7| 6| 7| 7| 6| 5| 6| 6| 7| 7| 7| 7| 7| 3| 7| 7| 7| 5| 7| 7| 5| 6| 7| 3|            |
                             DAY ON TEST   | 2| 3| 5| 3| 3| 1| 8| 5| 0| 2| 3| 3| 0| 3| 8| 3| 3| 3| 9| 3| 3| 8| 9| 3| 9|            |
                                           | 7| 4| 3| 4| 4| 1| 0| 3| 8| 3| 4| 4| 8| 4| 7| 4| 4| 4| 2| 4| 4| 9| 5| 4| 9|            |
 __________________________________________|__________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     A      |
    CONTROL                                | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|     L      |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |            |
                                           |                                                                          |            |
      Lymphoma Malignant                   |                X                                                         |          2 |
                                           |__________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Histiocytic Sarcoma                  |       X                                                                  |          1 |
      Lymphoma Malignant                   |                X                                                         |          3 |
                                           |__________________________________________________________________________|____________|
   Thymus                                  | +  +  M  +  +  +  M  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +|  41        |
      Lymphoma Malignant                   |                X                                                         |          1 |
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Mammary Gland                           | M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M|            |
                                           |__________________________________________________________________________|____________|
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Larynx                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Alveolar/Bronchiolar Adenoma         |             X                                X  X  X  X                  |          9 |
      Alveolar/Bronchiolar Adenoma,        |                                                                          |            |
          Multiple                         |                                                             X            |          3 |
      Alveolar/Bronchiolar Carcinoma       |                   X           X        X                 X               |          6 |
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                                                                                                    
                                                                                                                                    
                                                             Page  55                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 5| 7| 6| 7| 7| 6| 5| 6| 6| 7| 7| 7| 7| 7| 3| 7| 7| 7| 5| 7| 7| 5| 6| 7| 3|            |
                             DAY ON TEST   | 2| 3| 5| 3| 3| 1| 8| 5| 0| 2| 3| 3| 0| 3| 8| 3| 3| 3| 9| 3| 3| 8| 9| 3| 9|            |
                                           | 7| 4| 3| 4| 4| 1| 0| 3| 8| 3| 4| 4| 8| 4| 7| 4| 4| 4| 2| 4| 4| 9| 5| 4| 9|            |
 __________________________________________|__________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     A      |
    CONTROL                                | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|     L      |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 RESPIRATORY SYSTEM - cont                 |                                                                          |            |
                                           |                                                                          |            |
      Hepatocellular Carcinoma, Metastatic,|                                                                          |            |
           Liver                           |                         X                                                |          4 |
                                           |__________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Eye                                     |                                                                          |   2        |
                                           |__________________________________________________________________________|____________|
   Harderian Gland                         |                                  +                                   +   |   4        |
      Adenoma                              |                                                                          |          2 |
      Carcinoma                            |                                                                      X   |          1 |
      Bilateral, Adenoma                   |                                  X                                       |          1 |
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Lymphoma Malignant                   |                                                                          |          1 |
      Renal Tubule, Adenoma                |                                                    X                     |          1 |
                                           |__________________________________________________________________________|____________|
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +|  49        |
 __________________________________________________________________________________________________________________________________ 
 SYSTEMIC LESIONS                          |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Histiocytic Sarcoma                  |       X                                                                  |          1 |
      Lymphoma Malignant                   |             X  X                                                         |          4 |
 __________________________________________________________________________________________________________________________________ 
                                                                                                                                    
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  56                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 6| 7| 7| 7| 4| 5| 7| 7| 7| 5| 7| 7| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7|             
                             DAY ON TEST   | 3| 3| 3| 6| 3| 3| 3| 0| 4| 3| 3| 3| 9| 3| 3| 3| 1| 3| 3| 3| 3| 3| 5| 3| 3|             
                                           | 3| 3| 3| 7| 3| 3| 3| 5| 6| 3| 3| 3| 6| 3| 3| 3| 5| 3| 3| 3| 4| 4| 2| 4| 4|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|             
    500 PPM                                | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 ALIMENTARY SYSTEM                         |                                                                          |             
                                           |__________________________________________________________________________|             
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Gallbladder                             | +  +  M  A  M  +  +  A  I  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  +  +  A  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  I  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  A  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  A  +  +  +  A  A  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  A  +  +  +  A  A  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +|             
      Carcinoma                            |                                                                          |             
      Lymphoma Malignant                   |                                                             X            |             
                                           |__________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  A  +  +  +  A  A  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hepatocellular Carcinoma             |          X  X        X  X     X     X           X                        |             
      Hepatocellular Carcinoma, Multiple   |                                                                          |             
      Hepatocellular Adenoma               |    X        X  X        X  X  X     X  X  X  X     X              X      |             
      Hepatocellular Adenoma, Multiple     |                                  X                          X            |             
      Lymphoma Malignant                   |                                                             X            |             
                                           |__________________________________________________________________________|             
   Mesentery                               |                               +                                          |             
                                           |__________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |       X                                                                  |             
                                           |__________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  A  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  57                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 6| 7| 7| 7| 4| 5| 7| 7| 7| 5| 7| 7| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7|             
                             DAY ON TEST   | 3| 3| 3| 6| 3| 3| 3| 0| 4| 3| 3| 3| 9| 3| 3| 3| 1| 3| 3| 3| 3| 3| 5| 3| 3|             
                                           | 3| 3| 3| 7| 3| 3| 3| 5| 6| 3| 3| 3| 6| 3| 3| 3| 5| 3| 3| 3| 4| 4| 2| 4| 4|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|             
    500 PPM                                | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 ALIMENTARY SYSTEM - cont                  |                                                                          |             
                                           |                                                                          |             
   Tooth                                   |                   +              +     +     +              +  +  +  +   |             
      Odontoma                             |                                  X                                X      |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Pheochromocytoma Malignant,          |                                                                          |             
          Metastatic, Adrenal Medulla      |                                                    X                     |             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |__________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Adenoma                              |                                  X                                       |             
      Capsule, Adenoma                     |                                        X                                 |             
                                           |__________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Pheochromocytoma Malignant           |                                                    X                     |             
      Pheochromocytoma Benign              |                                                                         X|             
                                           |__________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Adenoma                              |                                        X                                 |             
                                           |__________________________________________________________________________|             
   Parathyroid Gland                       | +  +  +  M  +  +  +  +  M  +  +  M  +  +  +  +  +  +  M  +  +  +  +  +  M|             
                                           |__________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Preputial Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  58                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 6| 7| 7| 7| 4| 5| 7| 7| 7| 5| 7| 7| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7|             
                             DAY ON TEST   | 3| 3| 3| 6| 3| 3| 3| 0| 4| 3| 3| 3| 9| 3| 3| 3| 1| 3| 3| 3| 3| 3| 5| 3| 3|             
                                           | 3| 3| 3| 7| 3| 3| 3| 5| 6| 3| 3| 3| 6| 3| 3| 3| 5| 3| 3| 3| 4| 4| 2| 4| 4|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|             
    500 PPM                                | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 GENITAL SYSTEM - cont                     |                                                                          |             
                                           |                                                                          |             
                                           |__________________________________________________________________________|             
   Prostate                                | +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Seminal Vesicle                         | +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Lymph Node                              |       +                                   +                              |             
      Pancreatic, Lymphoma Malignant       |       X                                                                  |             
                                           |__________________________________________________________________________|             
   Lymph Node, Bronchial                   | M  +  +  +  +  +  +  M  M  +  +  +  M  +  M  +  M  +  +  M  +  +  +  M  +|             
      Lymphoma Malignant                   |       X                                                                  |             
      Pheochromocytoma Malignant,          |                                                                          |             
          Metastatic, Adrenal Medulla      |                                                    X                     |             
                                           |__________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  +  +  +  +  M  M  M  +  +  M  M  +  M  M  +  +  M  +  +  +  M  +  +|             
      Lymphoma Malignant                   |       X                                                                  |             
                                           |__________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |       X                                                     X            |             
                                           |__________________________________________________________________________|             
   Lymph Node, Mediastinal                 | +  +  +  M  +  M  M  +  +  +  +  M  M  +  M  +  M  +  M  +  +  +  M  +  +|             
      Lymphoma Malignant                   |       X                                                     X            |             
      Pheochromocytoma Malignant,          |                                                                          |             
          Metastatic, Adrenal Medulla      |                                                    X                     |             
                                           |__________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemangiosarcoma                      |                                                 X                        |             
      Lymphoma Malignant                   |       X                                                     X            |             
                                           |__________________________________________________________________________|             
   Thymus                                  | +  +  +  +  M  +  +  +  +  +  +  +  M  +  M  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                                                             X            |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  59                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 6| 7| 7| 7| 4| 5| 7| 7| 7| 5| 7| 7| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7|             
                             DAY ON TEST   | 3| 3| 3| 6| 3| 3| 3| 0| 4| 3| 3| 3| 9| 3| 3| 3| 1| 3| 3| 3| 3| 3| 5| 3| 3|             
                                           | 3| 3| 3| 7| 3| 3| 3| 5| 6| 3| 3| 3| 6| 3| 3| 3| 5| 3| 3| 3| 4| 4| 2| 4| 4|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|             
    500 PPM                                | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |__________________________________________________________________________|             
   Mammary Gland                           | M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M|             
                                           |__________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |__________________________________________________________________________|             
   Larynx                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Alveolar/Bronchiolar Adenoma         |                                  X                             X     X   |             
      Alveolar/Bronchiolar Adenoma,        |                                                                          |             
          Multiple                         |                                                                         X|             
      Alveolar/Bronchiolar Carcinoma       |       X                                      X     X  X                  |             
      Alveolar/Bronchiolar Carcinoma,      |                                                                          |             
          Multiple                         |                               X                                          |             
      Hepatocellular Carcinoma, Metastatic,|                                                                          |             
           Liver                           |                         X           X                                    |             
      Lymphoma Malignant                   |       X                                                     X            |             
      Pheochromocytoma Malignant,          |                                                                          |             
          Metastatic, Adrenal Medulla      |                                                    X                     |             
                                           |__________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Harderian Gland                         |       +                                                        +         |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  60                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 6| 7| 7| 7| 4| 5| 7| 7| 7| 5| 7| 7| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7|             
                             DAY ON TEST   | 3| 3| 3| 6| 3| 3| 3| 0| 4| 3| 3| 3| 9| 3| 3| 3| 1| 3| 3| 3| 3| 3| 5| 3| 3|             
                                           | 3| 3| 3| 7| 3| 3| 3| 5| 6| 3| 3| 3| 6| 3| 3| 3| 5| 3| 3| 3| 4| 4| 2| 4| 4|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|             
    500 PPM                                | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 SPECIAL SENSES SYSTEM - cont              |                                                                          |             
                                           |                                                                          |             
      Adenoma                              |       X                                                        X         |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hepatocellular Carcinoma, Metastatic,|                                                                          |             
           Liver                           |                                     X                                    |             
      Lymphoma Malignant                   |       X                                                                  |             
      Pheochromocytoma Malignant,          |                                                                          |             
          Metastatic, Adrenal Medulla      |                                                    X                     |             
                                           |__________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  A  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +|             
 __________________________________________|__________________________________________________________________________|             
 SYSTEMIC LESIONS                          |                                                                          |             
                                            __________________________________________________________________________|             
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |       X                                                     X            |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  61                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 6| 7| 6| 7| 6| 7| 7| 7| 5| 7| 5| 7| 5| 6| 7| 6| 7| 7| 7| 5| 7| 7|            |
                             DAY ON TEST   | 3| 1| 3| 3| 3| 9| 3| 6| 3| 3| 3| 1| 1| 6| 3| 2| 0| 3| 4| 3| 3| 0| 8| 3| 3|            |
                                           | 4| 1| 4| 9| 4| 8| 4| 7| 4| 4| 4| 2| 6| 2| 4| 2| 1| 4| 9| 4| 4| 9| 3| 4| 4|            |
 __________________________________________|__________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|     A      |
    500 PPM                                | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|     L      |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 ALIMENTARY SYSTEM                         |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Gallbladder                             | +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  A  A  M  +  +  +  +  +  +  +|  40        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Colon                  | +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +|  46        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Rectum                 | +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +|  46        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  A  A  +  +  +  +  +  +  +  +|  45        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  45        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  A  A  +  +  +  +  +  +  +  +|  43        |
      Carcinoma                            |          X                                                               |          1 |
      Lymphoma Malignant                   |                                                                          |          1 |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  A  A  +  +  +  +  +  +  +  +|  43        |
                                           |__________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hepatocellular Carcinoma             | X                                X           X     X              X      |         12 |
      Hepatocellular Carcinoma, Multiple   |    X                                                                     |          1 |
      Hepatocellular Adenoma               |             X  X  X                       X  X  X        X           X   |         20 |
      Hepatocellular Adenoma, Multiple     |          X                                                              X|          4 |
      Lymphoma Malignant                   |                                                                          |          1 |
                                           |__________________________________________________________________________|____________|
   Mesentery                               |                   +                                                      |   2        |
                                           |__________________________________________________________________________|____________|
   Pancreas                                | +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
                                           |__________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Lymphoma Malignant                   |                                                                          |          1 |
                                           |__________________________________________________________________________|____________|
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                                                                                                    
                                                                                                                                    
                                                             Page  62                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 6| 7| 6| 7| 6| 7| 7| 7| 5| 7| 5| 7| 5| 6| 7| 6| 7| 7| 7| 5| 7| 7|            |
                             DAY ON TEST   | 3| 1| 3| 3| 3| 9| 3| 6| 3| 3| 3| 1| 1| 6| 3| 2| 0| 3| 4| 3| 3| 0| 8| 3| 3|            |
                                           | 4| 1| 4| 9| 4| 8| 4| 7| 4| 4| 4| 2| 6| 2| 4| 2| 1| 4| 9| 4| 4| 9| 3| 4| 4|            |
 __________________________________________|__________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|     A      |
    500 PPM                                | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|     L      |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 ALIMENTARY SYSTEM - cont                  |                                                                          |            |
                                           |                                                                          |            |
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                           |__________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  47        |
                                           |__________________________________________________________________________|____________|
   Tooth                                   | +     +     +           +                             +                 +|  14        |
      Odontoma                             |                                                       X                  |          3 |
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Pheochromocytoma Malignant,          |                                                                          |            |
          Metastatic, Adrenal Medulla      |                                                                          |          1 |
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Adrenal Cortex                          | +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Adenoma                              |                                                                          |          1 |
      Capsule, Adenoma                     |                                                             X            |          2 |
                                           |__________________________________________________________________________|____________|
   Adrenal Medulla                         | +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Pheochromocytoma Malignant           |                                                                          |          1 |
      Pheochromocytoma Benign              |                                                                          |          1 |
                                           |__________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
      Adenoma                              |                                                                          |          1 |
                                           |__________________________________________________________________________|____________|
   Parathyroid Gland                       | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  M  +  M  +  +  +  +  +  +|  42        |
                                           |__________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
                                           |__________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
    None                                   |                                                                          |            |
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                             Page  63                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 6| 7| 6| 7| 6| 7| 7| 7| 5| 7| 5| 7| 5| 6| 7| 6| 7| 7| 7| 5| 7| 7|            |
                             DAY ON TEST   | 3| 1| 3| 3| 3| 9| 3| 6| 3| 3| 3| 1| 1| 6| 3| 2| 0| 3| 4| 3| 3| 0| 8| 3| 3|            |
                                           | 4| 1| 4| 9| 4| 8| 4| 7| 4| 4| 4| 2| 6| 2| 4| 2| 1| 4| 9| 4| 4| 9| 3| 4| 4|            |
 __________________________________________|__________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|     A      |
    500 PPM                                | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|     L      |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 GENITAL SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Preputial Gland                         | +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
                                           |__________________________________________________________________________|____________|
   Prostate                                | +  +  +  +  +  A  +  +  +  +  +  +  I  +  +  A  +  +  +  +  +  +  +  +  +|  46        |
                                           |__________________________________________________________________________|____________|
   Seminal Vesicle                         | +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +|  47        |
                                           |__________________________________________________________________________|____________|
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                           |__________________________________________________________________________|____________|
   Lymph Node                              |          +                                                               |   3        |
      Pancreatic, Lymphoma Malignant       |                                                                          |          1 |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Bronchial                   | +  +  M  +  +  M  M  +  M  +  +  +  +  M  +  +  +  +  M  +  +  M  +  M  M|  33        |
      Lymphoma Malignant                   |                                                                          |          1 |
      Pheochromocytoma Malignant,          |                                                                          |            |
          Metastatic, Adrenal Medulla      |                                                                          |          1 |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | +  +  +  M  +  M  M  M  M  +  M  +  +  +  +  M  M  +  +  M  M  +  +  M  M|  29        |
      Lymphoma Malignant                   |                                                                          |          1 |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Lymphoma Malignant                   |                                                                          |          2 |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mediastinal                 | +  +  +  +  +  M  +  +  +  +  +  +  +  M  M  +  +  +  +  +  +  +  +  +  +|  38        |
      Lymphoma Malignant                   |                                                                          |          2 |
      Pheochromocytoma Malignant,          |                                                                          |            |
          Metastatic, Adrenal Medulla      |                                                                          |          1 |
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                                                                                                    
                                                                                                                                    
                                                             Page  64                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 6| 7| 6| 7| 6| 7| 7| 7| 5| 7| 5| 7| 5| 6| 7| 6| 7| 7| 7| 5| 7| 7|            |
                             DAY ON TEST   | 3| 1| 3| 3| 3| 9| 3| 6| 3| 3| 3| 1| 1| 6| 3| 2| 0| 3| 4| 3| 3| 0| 8| 3| 3|            |
                                           | 4| 1| 4| 9| 4| 8| 4| 7| 4| 4| 4| 2| 6| 2| 4| 2| 1| 4| 9| 4| 4| 9| 3| 4| 4|            |
 __________________________________________|__________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|     A      |
    500 PPM                                | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|     L      |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |            |
                                           |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Hemangiosarcoma                      |                                                                          |          1 |
      Lymphoma Malignant                   |                                                                          |          2 |
                                           |__________________________________________________________________________|____________|
   Thymus                                  | +  +  +  +  +  A  +  +  +  +  +  +  +  +  M  M  +  M  +  +  M  +  +  +  +|  42        |
      Lymphoma Malignant                   |                                                                          |          1 |
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Mammary Gland                           | M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M|            |
                                           |__________________________________________________________________________|____________|
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Larynx                                  | +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                           |__________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Alveolar/Bronchiolar Adenoma         |                X                          X                              |          5 |
      Alveolar/Bronchiolar Adenoma,        |                                                                          |            |
          Multiple                         |                               X                                          |          2 |
      Alveolar/Bronchiolar Carcinoma       |                                                    X                     |          5 |
      Alveolar/Bronchiolar Carcinoma,      |                                                                          |            |
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                                                                                                    
                                                                                                                                    
                                                             Page  65                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 6| 7| 6| 7| 6| 7| 7| 7| 5| 7| 5| 7| 5| 6| 7| 6| 7| 7| 7| 5| 7| 7|            |
                             DAY ON TEST   | 3| 1| 3| 3| 3| 9| 3| 6| 3| 3| 3| 1| 1| 6| 3| 2| 0| 3| 4| 3| 3| 0| 8| 3| 3|            |
                                           | 4| 1| 4| 9| 4| 8| 4| 7| 4| 4| 4| 2| 6| 2| 4| 2| 1| 4| 9| 4| 4| 9| 3| 4| 4|            |
 __________________________________________|__________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|     A      |
    500 PPM                                | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|     L      |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 RESPIRATORY SYSTEM - cont                 |                                                                          |            |
                                           |                                                                          |            |
          Multiple                         |                                                                          |          1 |
      Hepatocellular Carcinoma, Metastatic,|                                                                          |            |
           Liver                           | X                                                  X                     |          4 |
      Lymphoma Malignant                   |                                                                          |          2 |
      Pheochromocytoma Malignant,          |                                                                          |            |
          Metastatic, Adrenal Medulla      |                                                                          |          1 |
                                           |__________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                           |__________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Harderian Gland                         |                            +  +                                          |   4        |
      Adenoma                              |                            X                                             |          3 |
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Hepatocellular Carcinoma, Metastatic,|                                                                          |            |
           Liver                           |                                                                          |          1 |
      Lymphoma Malignant                   |                                                                          |          1 |
      Pheochromocytoma Malignant,          |                                                                          |            |
          Metastatic, Adrenal Medulla      |                                                                          |          1 |
                                           |__________________________________________________________________________|____________|
   Urinary Bladder                         | +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  47        |
 __________________________________________________________________________________________________________________________________ 
 SYSTEMIC LESIONS                          |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Lymphoma Malignant                   |                                                                          |          2 |
 __________________________________________________________________________________________________________________________________ 
                                                                                                                                    
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  66                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 5| 7| 7| 5| 5| 7| 5| 7| 7| 4| 5| 7| 7| 7| 7| 7| 7| 5| 6| 7| 3| 7| 6| 7| 7|             
                             DAY ON TEST   | 2| 3| 3| 5| 8| 3| 5| 3| 3| 8| 8| 3| 3| 3| 3| 3| 3| 1| 2| 3| 8| 3| 8| 3| 0|             
                                           | 7| 3| 3| 5| 4| 3| 9| 3| 3| 0| 3| 3| 3| 3| 3| 3| 3| 2| 8| 3| 7| 3| 1| 3| 8|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4|             
    2000 PPM                               | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 ALIMENTARY SYSTEM                         |                                                                          |             
                                           |__________________________________________________________________________|             
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Gallbladder                             | +  +  +  +  A  I  +  +  +  A  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                                                                          |             
                                           |__________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  A  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                                                                          |             
                                           |__________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  A  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                      X                                                   |             
                                           |__________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  A  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                                                                          |             
                                           |__________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemangiosarcoma                      |       X           X                                                      |             
      Hepatoblastoma                       |                                                                          |             
      Hepatocellular Carcinoma             |             X           X     X                                      X   |             
      Hepatocellular Carcinoma, Multiple   |          X                                         X                     |             
      Hepatocellular Adenoma               |    X        X  X     X  X                                         X     X|             
      Hepatocellular Adenoma, Multiple     |                                           X  X                 X         |             
      Histiocytic Sarcoma                  |                                                                         X|             
      Lymphoma Malignant                   |                                                                   X      |             
                                           |__________________________________________________________________________|             
   Mesentery                               |    +                                                        +            |             
                                           |__________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                                                                   X      |             
                                           |__________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  67                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 5| 7| 7| 5| 5| 7| 5| 7| 7| 4| 5| 7| 7| 7| 7| 7| 7| 5| 6| 7| 3| 7| 6| 7| 7|             
                             DAY ON TEST   | 2| 3| 3| 5| 8| 3| 5| 3| 3| 8| 8| 3| 3| 3| 3| 3| 3| 1| 2| 3| 8| 3| 8| 3| 0|             
                                           | 7| 3| 3| 5| 4| 3| 9| 3| 3| 0| 3| 3| 3| 3| 3| 3| 3| 2| 8| 3| 7| 3| 1| 3| 8|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4|             
    2000 PPM                               | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 ALIMENTARY SYSTEM - cont                  |                                                                          |             
                                           |                                                                          |             
      Lymphoma Malignant                   |                                                                          |             
                                           |__________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Tooth                                   |                         +  +     +  +  +                       +     +   |             
      Odontoma                             |                         X        X                                       |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |__________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Adenoma                              |                                                                          |             
      Lymphoma Malignant                   |                                                                          |             
                                           |__________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                                                                          |             
      Pheochromocytoma Benign              |                                                                          |             
                                           |__________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Parathyroid Gland                       | +  +  +  +  +  +  M  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Follicular Cell, Adenoma             |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  68                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 5| 7| 7| 5| 5| 7| 5| 7| 7| 4| 5| 7| 7| 7| 7| 7| 7| 5| 6| 7| 3| 7| 6| 7| 7|             
                             DAY ON TEST   | 2| 3| 3| 5| 8| 3| 5| 3| 3| 8| 8| 3| 3| 3| 3| 3| 3| 1| 2| 3| 8| 3| 8| 3| 0|             
                                           | 7| 3| 3| 5| 4| 3| 9| 3| 3| 0| 3| 3| 3| 3| 3| 3| 3| 2| 8| 3| 7| 3| 1| 3| 8|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4|             
    2000 PPM                               | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 GENITAL SYSTEM - cont                     |                                                                          |             
                                           |                                                                          |             
                                           |__________________________________________________________________________|             
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                                                                   X      |             
                                           |__________________________________________________________________________|             
   Penis                                   |          +                                                               |             
                                           |__________________________________________________________________________|             
   Preputial Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Prostate                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                                                                          |             
                                           |__________________________________________________________________________|             
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                                                                          |             
                                           |__________________________________________________________________________|             
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Interstitial Cell, Adenoma           |                                        X                                 |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Histiocytic Sarcoma                  |                                                                         X|             
                                           |__________________________________________________________________________|             
   Lymph Node                              |                                                       +           +      |             
      Lymphoma Malignant                   |                                                                          |             
      Iliac, Lymphoma Malignant            |                                                                   X      |             
      Pancreatic, Lymphoma Malignant       |                                                                          |             
      Renal, Lymphoma Malignant            |                                                                   X      |             
                                           |__________________________________________________________________________|             
   Lymph Node, Bronchial                   | +  M  +  +  +  +  M  M  M  +  M  M  +  +  M  M  +  +  +  M  +  +  +  +  M|             
      Lymphoma Malignant                   |                                                                   X      |             
                                           |__________________________________________________________________________|             
   Lymph Node, Mandibular                  | M  +  +  M  M  +  +  M  +  M  +  +  M  +  +  +  M  M  +  M  +  +  +  M  +|             
      Lymphoma Malignant                   |                                                                   X      |             
                                           |__________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +|             
      Histiocytic Sarcoma                  |                                                                         X|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  69                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 5| 7| 7| 5| 5| 7| 5| 7| 7| 4| 5| 7| 7| 7| 7| 7| 7| 5| 6| 7| 3| 7| 6| 7| 7|             
                             DAY ON TEST   | 2| 3| 3| 5| 8| 3| 5| 3| 3| 8| 8| 3| 3| 3| 3| 3| 3| 1| 2| 3| 8| 3| 8| 3| 0|             
                                           | 7| 3| 3| 5| 4| 3| 9| 3| 3| 0| 3| 3| 3| 3| 3| 3| 3| 2| 8| 3| 7| 3| 1| 3| 8|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4|             
    2000 PPM                               | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |             
                                           |                                                                          |             
      Lymphoma Malignant                   |                      X                                            X      |             
                                           |__________________________________________________________________________|             
   Lymph Node, Mediastinal                 | +  M  +  +  +  M  M  +  +  +  +  +  M  +  +  +  +  M  M  +  +  M  M  M  +|             
      Histiocytic Sarcoma                  |                                                                         X|             
      Lymphoma Malignant                   |                                                                          |             
                                           |__________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Histiocytic Sarcoma                  |                                                                         X|             
      Lymphoma Malignant                   |                                                                   X      |             
                                           |__________________________________________________________________________|             
   Thymus                                  | +  +  M  M  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +|             
      Lymphoma Malignant                   |                                                                   X      |             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |__________________________________________________________________________|             
   Mammary Gland                           | M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M|             
                                           |__________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Subcutaneous Tissue, Hemangioma      |                                                                          |             
      Subcutaneous Tissue, Sarcoma         |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |__________________________________________________________________________|             
   Larynx                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Alveolar/Bronchiolar Adenoma         |                X              X                                X         |             
      Alveolar/Bronchiolar Carcinoma       |                      X                                                   |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  70                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 5| 7| 7| 5| 5| 7| 5| 7| 7| 4| 5| 7| 7| 7| 7| 7| 7| 5| 6| 7| 3| 7| 6| 7| 7|             
                             DAY ON TEST   | 2| 3| 3| 5| 8| 3| 5| 3| 3| 8| 8| 3| 3| 3| 3| 3| 3| 1| 2| 3| 8| 3| 8| 3| 0|             
                                           | 7| 3| 3| 5| 4| 3| 9| 3| 3| 0| 3| 3| 3| 3| 3| 3| 3| 2| 8| 3| 7| 3| 1| 3| 8|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4|             
    2000 PPM                               | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 RESPIRATORY SYSTEM - cont                 |                                                                          |             
                                           |                                                                          |             
      Hepatocellular Carcinoma, Metastatic,|                                                                          |             
           Liver                           |          X                    X                                          |             
      Histiocytic Sarcoma                  |                                                                         X|             
      Lymphoma Malignant                   |                                                                   X      |             
                                           |__________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Harderian Gland                         |                                                                      +   |             
      Adenoma                              |                                                                      X   |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Histiocytic Sarcoma                  |                                                                         X|             
      Lymphoma Malignant                   |                                                                   X      |             
      Renal Tubule, Adenoma                |                                                                          |             
                                           |__________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 __________________________________________|__________________________________________________________________________|             
 SYSTEMIC LESIONS                          |                                                                          |             
                                            __________________________________________________________________________|             
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Histiocytic Sarcoma                  |                                                                         X|             
      Lymphoma Malignant                   |                      X                                            X      |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  71                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 6| 4| 7| 5| 7| 4| 7| 7| 7| 7| 7| 6| 6| 7| 6| 3| 7| 7| 7| 7| 7| 6| 7| 6| 7|            |
                             DAY ON TEST   | 3| 9| 3| 1| 3| 2| 3| 3| 3| 3| 3| 3| 3| 3| 4| 8| 3| 3| 3| 2| 3| 5| 3| 8| 1|            |
                                           | 1| 9| 3| 2| 4| 8| 4| 4| 4| 4| 4| 6| 9| 4| 5| 9| 4| 4| 4| 9| 4| 3| 4| 6| 3|            |
 __________________________________________|__________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4|     A      |
    2000 PPM                               | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|     L      |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 ALIMENTARY SYSTEM                         |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Gallbladder                             | +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  45        |
      Lymphoma Malignant                   | X                                                                        |          1 |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
      Lymphoma Malignant                   |                                                                      X   |          1 |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
      Lymphoma Malignant                   | X                                                                        |          2 |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
      Lymphoma Malignant                   | X                                                                        |          1 |
                                           |__________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hemangiosarcoma                      |                                                                          |          2 |
      Hepatoblastoma                       |                                                                   X      |          1 |
      Hepatocellular Carcinoma             |             X                             X  X                 X  X     X|         10 |
      Hepatocellular Carcinoma, Multiple   |          X                 X                                             |          4 |
      Hepatocellular Adenoma               |       X              X     X        X     X           X                  |         13 |
      Hepatocellular Adenoma, Multiple     | X                       X                                                |          5 |
      Histiocytic Sarcoma                  |                                                                          |          1 |
      Lymphoma Malignant                   | X                                                                    X   |          3 |
                                           |__________________________________________________________________________|____________|
   Mesentery                               | +                             +                                          |   4        |
                                           |__________________________________________________________________________|____________|
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                                                                                                    
                                                                                                                                    
                                                             Page  72                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 6| 4| 7| 5| 7| 4| 7| 7| 7| 7| 7| 6| 6| 7| 6| 3| 7| 7| 7| 7| 7| 6| 7| 6| 7|            |
                             DAY ON TEST   | 3| 9| 3| 1| 3| 2| 3| 3| 3| 3| 3| 3| 3| 3| 4| 8| 3| 3| 3| 2| 3| 5| 3| 8| 1|            |
                                           | 1| 9| 3| 2| 4| 8| 4| 4| 4| 4| 4| 6| 9| 4| 5| 9| 4| 4| 4| 9| 4| 3| 4| 6| 3|            |
 __________________________________________|__________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4|     A      |
    2000 PPM                               | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|     L      |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 ALIMENTARY SYSTEM - cont                  |                                                                          |            |
                                           |                                                                          |            |
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Lymphoma Malignant                   | X                                                                        |          2 |
                                           |__________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Lymphoma Malignant                   | X                                                                        |          1 |
                                           |__________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                           |__________________________________________________________________________|____________|
   Tooth                                   |       +                                                              +   |   9        |
      Odontoma                             |                                                                          |          2 |
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Adenoma                              |                                                       X                  |          1 |
      Lymphoma Malignant                   | X                                                                        |          1 |
                                           |__________________________________________________________________________|____________|
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Lymphoma Malignant                   | X                                                                        |          1 |
      Pheochromocytoma Benign              |                                                    X                     |          1 |
                                           |__________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Parathyroid Gland                       | +  M  +  M  +  +  +  +  +  M  M  +  +  +  +  +  +  +  +  +  +  M  +  +  M|  42        |
                                           |__________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +|  49        |
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                                                                                                    
                                                                                                                                    
                                                             Page  73                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 6| 4| 7| 5| 7| 4| 7| 7| 7| 7| 7| 6| 6| 7| 6| 3| 7| 7| 7| 7| 7| 6| 7| 6| 7|            |
                             DAY ON TEST   | 3| 9| 3| 1| 3| 2| 3| 3| 3| 3| 3| 3| 3| 3| 4| 8| 3| 3| 3| 2| 3| 5| 3| 8| 1|            |
                                           | 1| 9| 3| 2| 4| 8| 4| 4| 4| 4| 4| 6| 9| 4| 5| 9| 4| 4| 4| 9| 4| 3| 4| 6| 3|            |
 __________________________________________|__________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4|     A      |
    2000 PPM                               | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|     L      |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 ENDOCRINE SYSTEM - cont                   |                                                                          |            |
                                           |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Follicular Cell, Adenoma             |                                  X                                       |          1 |
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
    None                                   |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Lymphoma Malignant                   | X                                                                        |          2 |
                                           |__________________________________________________________________________|____________|
   Penis                                   |                                  +                                       |   2        |
                                           |__________________________________________________________________________|____________|
   Preputial Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Prostate                                | +  M  +  I  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  47        |
      Lymphoma Malignant                   | X                                                                        |          1 |
                                           |__________________________________________________________________________|____________|
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Lymphoma Malignant                   | X                                                                        |          1 |
                                           |__________________________________________________________________________|____________|
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Interstitial Cell, Adenoma           |                                                                          |          1 |
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Histiocytic Sarcoma                  |                                                                          |          1 |
                                           |__________________________________________________________________________|____________|
   Lymph Node                              | +  +                             +        +                          +   |   7        |
      Lymphoma Malignant                   |                                           X                              |          1 |
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                                                                                                    
                                                                                                                                    
                                                             Page  74                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 6| 4| 7| 5| 7| 4| 7| 7| 7| 7| 7| 6| 6| 7| 6| 3| 7| 7| 7| 7| 7| 6| 7| 6| 7|            |
                             DAY ON TEST   | 3| 9| 3| 1| 3| 2| 3| 3| 3| 3| 3| 3| 3| 3| 4| 8| 3| 3| 3| 2| 3| 5| 3| 8| 1|            |
                                           | 1| 9| 3| 2| 4| 8| 4| 4| 4| 4| 4| 6| 9| 4| 5| 9| 4| 4| 4| 9| 4| 3| 4| 6| 3|            |
 __________________________________________|__________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4|     A      |
    2000 PPM                               | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|     L      |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |            |
                                           |                                                                          |            |
      Iliac, Lymphoma Malignant            | X                                         X                              |          3 |
      Pancreatic, Lymphoma Malignant       |                                           X                          X   |          2 |
      Renal, Lymphoma Malignant            | X                                         X                              |          3 |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Bronchial                   | +  +  M  M  +  M  +  +  M  +  +  +  +  +  +  M  +  +  M  M  +  +  +  +  M|  32        |
      Lymphoma Malignant                   | X                                         X                          X   |          4 |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | +  +  +  M  +  +  +  +  M  +  +  +  +  +  +  +  +  M  +  +  M  +  M  M  M|  33        |
      Lymphoma Malignant                   | X                                         X                              |          3 |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +|  48        |
      Histiocytic Sarcoma                  |                                                                          |          1 |
      Lymphoma Malignant                   | X                                         X                          X   |          5 |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mediastinal                 | +  +  M  +  +  +  M  +  +  +  +  M  M  +  +  +  +  M  +  +  +  +  +  +  +|  36        |
      Histiocytic Sarcoma                  |                                                                          |          1 |
      Lymphoma Malignant                   | X                                         X                          X   |          3 |
                                           |__________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Histiocytic Sarcoma                  |                                                                          |          1 |
      Lymphoma Malignant                   | X                                         X                              |          3 |
                                           |__________________________________________________________________________|____________|
   Thymus                                  | M  +  +  +  M  M  +  +  +  M  M  +  +  +  +  +  +  +  +  +  +  M  +  M  M|  38        |
      Lymphoma Malignant                   |                                                                          |          1 |
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Mammary Gland                           | M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M|            |
                                           |__________________________________________________________________________|____________|
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Subcutaneous Tissue, Hemangioma      |                                                       X                  |          1 |
      Subcutaneous Tissue, Sarcoma         |          X                                                               |          1 |
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                                                                                                    
                                                                                                                                    
                                                             Page  75                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 6| 4| 7| 5| 7| 4| 7| 7| 7| 7| 7| 6| 6| 7| 6| 3| 7| 7| 7| 7| 7| 6| 7| 6| 7|            |
                             DAY ON TEST   | 3| 9| 3| 1| 3| 2| 3| 3| 3| 3| 3| 3| 3| 3| 4| 8| 3| 3| 3| 2| 3| 5| 3| 8| 1|            |
                                           | 1| 9| 3| 2| 4| 8| 4| 4| 4| 4| 4| 6| 9| 4| 5| 9| 4| 4| 4| 9| 4| 3| 4| 6| 3|            |
 __________________________________________|__________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4|     A      |
    2000 PPM                               | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|     L      |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Larynx                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Alveolar/Bronchiolar Adenoma         |                                                       X           X      |          5 |
      Alveolar/Bronchiolar Carcinoma       |                         X  X                                X            |          4 |
      Hepatocellular Carcinoma, Metastatic,|                                                                          |            |
           Liver                           |                                                                          |          2 |
      Histiocytic Sarcoma                  |                                                                          |          1 |
      Lymphoma Malignant                   | X                                         X                              |          3 |
                                           |__________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Harderian Gland                         | +                                                              +        +|   4        |
      Adenoma                              | X                                                              X        X|          4 |
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Histiocytic Sarcoma                  |                                                                          |          1 |
      Lymphoma Malignant                   | X                                                                        |          2 |
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                                                                                                    
                                                                                                                                    
                                                             Page  76                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 6| 4| 7| 5| 7| 4| 7| 7| 7| 7| 7| 6| 6| 7| 6| 3| 7| 7| 7| 7| 7| 6| 7| 6| 7|            |
                             DAY ON TEST   | 3| 9| 3| 1| 3| 2| 3| 3| 3| 3| 3| 3| 3| 3| 4| 8| 3| 3| 3| 2| 3| 5| 3| 8| 1|            |
                                           | 1| 9| 3| 2| 4| 8| 4| 4| 4| 4| 4| 6| 9| 4| 5| 9| 4| 4| 4| 9| 4| 3| 4| 6| 3|            |
 __________________________________________|__________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4|     A      |
    2000 PPM                               | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|     L      |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 URINARY SYSTEM - cont                     |                                                                          |            |
                                           |                                                                          |            |
      Renal Tubule, Adenoma                |                                                    X  X                  |          2 |
                                           |__________________________________________________________________________|____________|
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
 __________________________________________________________________________________________________________________________________ 
 SYSTEMIC LESIONS                          |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Histiocytic Sarcoma                  |                                                                          |          1 |
      Lymphoma Malignant                   | X                                         X                          X   |          5 |
 __________________________________________________________________________________________________________________________________ 
                                                                                                                                    
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  77                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 3| 4| 6| 7| 7| 7| 7| 4| 7| 5| 6| 6| 6| 5| 7| 7| 6| 7| 7| 7| 5| 7| 7|             
                             DAY ON TEST   | 3| 2| 4| 9| 6| 3| 3| 3| 3| 5| 3| 4| 3| 8| 0| 6| 3| 3| 8| 3| 3| 3| 1| 3| 3|             
                                           | 3| 7| 1| 9| 7| 3| 3| 3| 3| 7| 3| 7| 3| 9| 8| 2| 3| 3| 2| 3| 3| 3| 2| 3| 3|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6|             
    8000 PPM                               | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 ALIMENTARY SYSTEM                         |                                                                          |             
                                           |__________________________________________________________________________|             
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Gallbladder                             | +  +  A  +  M  +  +  +  M  +  M  M  +  A  I  +  +  +  A  M  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  A  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  A  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  A  +  +  +  +  +  +|             
      Leiomyoma                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  A  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  A  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  A  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  A  +  +  +  +  +  +|             
      Carcinoma                            |                                                                X         |             
      Lymphoma Malignant                   |             X                                                            |             
                                           |__________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  A  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  A  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +|             
      Hemangiosarcoma                      |                X        X                                                |             
      Hepatocellular Carcinoma             |          X                                   X                 X         |             
      Hepatocellular Carcinoma, Multiple   |             X                 X  X        X                              |             
      Hepatocellular Adenoma               |                         X           X              X        X            |             
      Hepatocellular Adenoma, Multiple     | X  X                 X                                         X     X   |             
                                           |__________________________________________________________________________|             
   Mesentery                               | +                                               +                        |             
                                           |__________________________________________________________________________|             
   Pancreas                                | +  +  A  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  A  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Stomach, Glandular                      | +  +  A  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  A  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  78                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 3| 4| 6| 7| 7| 7| 7| 4| 7| 5| 6| 6| 6| 5| 7| 7| 6| 7| 7| 7| 5| 7| 7|             
                             DAY ON TEST   | 3| 2| 4| 9| 6| 3| 3| 3| 3| 5| 3| 4| 3| 8| 0| 6| 3| 3| 8| 3| 3| 3| 1| 3| 3|             
                                           | 3| 7| 1| 9| 7| 3| 3| 3| 3| 7| 3| 7| 3| 9| 8| 2| 3| 3| 2| 3| 3| 3| 2| 3| 3|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6|             
    8000 PPM                               | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 ALIMENTARY SYSTEM - cont                  |                                                                          |             
                                           |                                                                          |             
   Tooth                                   |                +  +     +              +        +        +  +  +        +|             
      Odontoma                             |                                                             X            |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemangiosarcoma                      |                X                                                         |             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |__________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +|             
      Capsule, Adenoma                     |                                                    X                     |             
                                           |__________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +|             
      Pheochromocytoma Benign              |                   X                 X                                    |             
                                           |__________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  A  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Parathyroid Gland                       | +  +  +  +  M  +  +  +  +  M  +  +  +  +  +  +  +  +  M  +  +  +  M  +  M|             
                                           |__________________________________________________________________________|             
   Pituitary Gland                         | +  +  I  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Pars Intermedia, Adenoma             |                                                                X         |             
                                           |__________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Preputial Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Prostate                                | +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  79                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 3| 4| 6| 7| 7| 7| 7| 4| 7| 5| 6| 6| 6| 5| 7| 7| 6| 7| 7| 7| 5| 7| 7|             
                             DAY ON TEST   | 3| 2| 4| 9| 6| 3| 3| 3| 3| 5| 3| 4| 3| 8| 0| 6| 3| 3| 8| 3| 3| 3| 1| 3| 3|             
                                           | 3| 7| 1| 9| 7| 3| 3| 3| 3| 7| 3| 7| 3| 9| 8| 2| 3| 3| 2| 3| 3| 3| 2| 3| 3|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6|             
    8000 PPM                               | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 GENITAL SYSTEM - cont                     |                                                                          |             
                                           |                                                                          |             
   Seminal Vesicle                         | +  +  A  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  A  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Interstitial Cell, Adenoma           |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Lymph Node                              |             +                                                            |             
                                           |__________________________________________________________________________|             
   Lymph Node, Bronchial                   | +  +  M  M  +  +  +  +  +  M  +  +  +  M  +  +  +  M  +  +  +  +  M  +  +|             
      Lymphoma Malignant                   | X                                                                        |             
                                           |__________________________________________________________________________|             
   Lymph Node, Mandibular                  | M  +  M  +  +  +  +  +  +  +  +  M  +  +  +  +  M  M  M  +  M  +  +  +  +|             
      Lymphoma Malignant                   |                         X                                                |             
                                           |__________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   | X                       X                             X                  |             
                                           |__________________________________________________________________________|             
   Lymph Node, Mediastinal                 | +  M  +  +  M  M  +  M  +  M  M  +  +  M  +  +  M  +  +  M  +  M  M  +  +|             
      Lymphoma Malignant                   |                         X                                                |             
                                           |__________________________________________________________________________|             
   Spleen                                  | +  +  A  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +|             
      Hemangiosarcoma                      |                X                                                         |             
      Histiocytic Sarcoma                  |                X                                                         |             
      Lymphoma Malignant                   |                         X                             X                  |             
                                           |__________________________________________________________________________|             
   Thymus                                  | +  M  +  +  +  +  +  +  +  +  +  +  +  A  M  +  +  +  +  M  +  +  M  +  +|             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |__________________________________________________________________________|             
   Mammary Gland                           | M  M  M  M  M  M  +  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M|             
                                           |__________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Subcutaneous Tissue, Sarcoma         |                                                                          |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  80                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 3| 4| 6| 7| 7| 7| 7| 4| 7| 5| 6| 6| 6| 5| 7| 7| 6| 7| 7| 7| 5| 7| 7|             
                             DAY ON TEST   | 3| 2| 4| 9| 6| 3| 3| 3| 3| 5| 3| 4| 3| 8| 0| 6| 3| 3| 8| 3| 3| 3| 1| 3| 3|             
                                           | 3| 7| 1| 9| 7| 3| 3| 3| 3| 7| 3| 7| 3| 9| 8| 2| 3| 3| 2| 3| 3| 3| 2| 3| 3|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6|             
    8000 PPM                               | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |__________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Peripheral Nerve                        |                                     +                                    |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |__________________________________________________________________________|             
   Larynx                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  A  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Alveolar/Bronchiolar Adenoma         |                                                          X               |             
      Alveolar/Bronchiolar Carcinoma       | X                                               X                        |             
      Alveolar/Bronchiolar Carcinoma,      |                                                                          |             
          Multiple                         |                                                                      X   |             
      Hepatocellular Carcinoma, Metastatic,|                                                                          |             
           Liver                           |                                  X           X                           |             
      Lymphoma Malignant                   | X                                                                        |             
                                           |__________________________________________________________________________|             
   Nose                                    | +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +|             
                                           |__________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Eye                                     |                                                                          |             
                                           |__________________________________________________________________________|             
   Harderian Gland                         | +                                                              +         |             
      Adenoma                              | X                                                              X         |             
      Carcinoma                            |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |__________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  81                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 3| 4| 6| 7| 7| 7| 7| 4| 7| 5| 6| 6| 6| 5| 7| 7| 6| 7| 7| 7| 5| 7| 7|             
                             DAY ON TEST   | 3| 2| 4| 9| 6| 3| 3| 3| 3| 5| 3| 4| 3| 8| 0| 6| 3| 3| 8| 3| 3| 3| 1| 3| 3|             
                                           | 3| 7| 1| 9| 7| 3| 3| 3| 3| 7| 3| 7| 3| 9| 8| 2| 3| 3| 2| 3| 3| 3| 2| 3| 3|             
 __________________________________________|__________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6|             
    8000 PPM                               | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 __________________________________________|__________________________________________________________________________|             
 URINARY SYSTEM - cont                     |                                                                          |             
                                           |                                                                          |             
                                           |__________________________________________________________________________|             
   Urinary Bladder                         | +  +  A  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  A  +  +  +  +  +  +|             
 __________________________________________|__________________________________________________________________________|             
 SYSTEMIC LESIONS                          |                                                                          |             
                                            __________________________________________________________________________|             
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Histiocytic Sarcoma                  |                X                                                         |             
      Lymphoma Malignant                   | X           X           X                             X                  |             
 __________________________________________|__________________________________________________________________________|             
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  82                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 5| 6| 3| 3| 6| 7| 7| 6| 2| 6| 7| 7| 7| 7| 5|            |
                             DAY ON TEST   | 3| 3| 3| 3| 3| 3| 0| 3| 3| 3| 4| 7| 3| 8| 3| 3| 3| 9| 5| 3| 3| 3| 3| 3| 0|            |
                                           | 3| 4| 4| 4| 4| 4| 6| 4| 4| 4| 7| 0| 0| 6| 9| 4| 4| 5| 1| 1| 4| 4| 4| 4| 8|            |
 __________________________________________|__________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6|     A      |
    8000 PPM                               | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|     L      |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 ALIMENTARY SYSTEM                         |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Gallbladder                             | +  +  +  +  +  +  A  +  +  +  M  A  A  A  +  +  +  +  +  +  M  +  +  +  M|  34        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  I  +  +|  46        |
                                           |__________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +  +  +  +  +  A  +  +  +  +  A  A  +  +  +  +  +  A  +  +  +  +  +  A|  42        |
      Leiomyoma                            |                                                                   X      |          1 |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  A  A  A  +  +  +  +  A  +  +  +  +  +  A|  42        |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  A  A  +  +  +  +  +  A  +  +  +  +  +  A|  43        |
      Carcinoma                            |                                                                          |          1 |
      Lymphoma Malignant                   |                                                                          |          1 |
                                           |__________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +  +  +  +  +  A  +  +  +  +  A  A  +  +  +  +  +  A  +  +  +  +  +  A|  42        |
                                           |__________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Hemangiosarcoma                      |                                                                          |          2 |
      Hepatocellular Carcinoma             |                               X     X  X                          X      |          7 |
      Hepatocellular Carcinoma, Multiple   |          X                       X                                      X|          7 |
      Hepatocellular Adenoma               |                X  X                 X        X                 X     X   |         10 |
      Hepatocellular Adenoma, Multiple     |       X                    X                                             |          7 |
                                           |__________________________________________________________________________|____________|
   Mesentery                               |                                                                          |   2        |
                                           |__________________________________________________________________________|____________|
   Pancreas                                | +  +  I  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  47        |
                                           |__________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                                                                                                    
                                                                                                                                    
                                                             Page  83                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 5| 6| 3| 3| 6| 7| 7| 6| 2| 6| 7| 7| 7| 7| 5|            |
                             DAY ON TEST   | 3| 3| 3| 3| 3| 3| 0| 3| 3| 3| 4| 7| 3| 8| 3| 3| 3| 9| 5| 3| 3| 3| 3| 3| 0|            |
                                           | 3| 4| 4| 4| 4| 4| 6| 4| 4| 4| 7| 0| 0| 6| 9| 4| 4| 5| 1| 1| 4| 4| 4| 4| 8|            |
 __________________________________________|__________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6|     A      |
    8000 PPM                               | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|     L      |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 ALIMENTARY SYSTEM - cont                  |                                                                          |            |
                                           |                                                                          |            |
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
                                           |__________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +|  46        |
                                           |__________________________________________________________________________|____________|
   Tooth                                   |    +                    +  +     +           +  +           +            |  16        |
      Odontoma                             |                         X                                                |          2 |
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hemangiosarcoma                      |                                                                          |          1 |
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Capsule, Adenoma                     | X     X                                                                  |          3 |
                                           |__________________________________________________________________________|____________|
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Pheochromocytoma Benign              |                                                                          |          2 |
                                           |__________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
                                           |__________________________________________________________________________|____________|
   Parathyroid Gland                       | M  +  M  +  +  M  +  +  +  M  +  M  +  +  +  +  M  +  M  +  +  +  +  M  +|  37        |
                                           |__________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  I|  48        |
      Pars Intermedia, Adenoma             |                                                                          |          1 |
                                           |__________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
    None                                   |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
                                                                                                                                    
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                                                                                                    
                                                                                                                                    
                                                             Page  84                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 5| 6| 3| 3| 6| 7| 7| 6| 2| 6| 7| 7| 7| 7| 5|            |
                             DAY ON TEST   | 3| 3| 3| 3| 3| 3| 0| 3| 3| 3| 4| 7| 3| 8| 3| 3| 3| 9| 5| 3| 3| 3| 3| 3| 0|            |
                                           | 3| 4| 4| 4| 4| 4| 6| 4| 4| 4| 7| 0| 0| 6| 9| 4| 4| 5| 1| 1| 4| 4| 4| 4| 8|            |
 __________________________________________|__________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6|     A      |
    8000 PPM                               | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|     L      |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 GENITAL SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Preputial Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Prostate                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +|  48        |
                                           |__________________________________________________________________________|____________|
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  47        |
                                           |__________________________________________________________________________|____________|
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Interstitial Cell, Adenoma           |                                                 X                        |          1 |
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                           |__________________________________________________________________________|____________|
   Lymph Node                              |                                                                          |   1        |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Bronchial                   | +  +  +  +  +  +  M  M  M  +  M  M  +  M  +  +  +  M  M  +  +  M  M  M  M|  32        |
      Lymphoma Malignant                   |                                                                          |          1 |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | +  M  +  +  +  M  +  +  M  +  M  M  M  +  +  M  +  +  +  +  +  +  +  +  M|  35        |
      Lymphoma Malignant                   |                                                                          |          1 |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Lymphoma Malignant                   |          X                                                               |          4 |
                                           |__________________________________________________________________________|____________|
   Lymph Node, Mediastinal                 | +  +  +  M  +  +  M  M  +  +  M  +  M  +  +  +  +  M  +  +  M  +  +  M  +|  31        |
      Lymphoma Malignant                   |                                                                          |          1 |
                                           |__________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
      Hemangiosarcoma                      |                                                                          |          1 |
      Histiocytic Sarcoma                  |                                                                          |          1 |
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                                                                                                    
                                                                                                                                    
                                                             Page  85                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 5| 6| 3| 3| 6| 7| 7| 6| 2| 6| 7| 7| 7| 7| 5|            |
                             DAY ON TEST   | 3| 3| 3| 3| 3| 3| 0| 3| 3| 3| 4| 7| 3| 8| 3| 3| 3| 9| 5| 3| 3| 3| 3| 3| 0|            |
                                           | 3| 4| 4| 4| 4| 4| 6| 4| 4| 4| 7| 0| 0| 6| 9| 4| 4| 5| 1| 1| 4| 4| 4| 4| 8|            |
 __________________________________________|__________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6|     A      |
    8000 PPM                               | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|     L      |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |            |
                                           |                                                                          |            |
      Lymphoma Malignant                   |          X                                                               |          3 |
                                           |__________________________________________________________________________|____________|
   Thymus                                  | +  +  M  +  +  +  +  +  +  +  M  M  +  M  +  +  +  +  +  +  +  +  +  +  +|  41        |
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Mammary Gland                           | M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M  M|   1        |
                                           |__________________________________________________________________________|____________|
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Subcutaneous Tissue, Sarcoma         |                                                                         X|          1 |
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Peripheral Nerve                        |                                                                          |   1        |
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Larynx                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
                                           |__________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Alveolar/Bronchiolar Adenoma         |                                                 X              X         |          3 |
      Alveolar/Bronchiolar Carcinoma       |                                              X                           |          3 |
      Alveolar/Bronchiolar Carcinoma,      |                                                                          |            |
          Multiple                         |    X                                                              X      |          3 |
      Hepatocellular Carcinoma, Metastatic,|                                                                          |            |
           Liver                           |                                                                         X|          3 |
 _____________________________________________________________________________________________________________________|____________|
                                                                                                                                    
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                                                                                                    
                                                                                                                                    
                                                             Page  86                                                               
                                                                                                                                   
NTP Experiment-Test: 88070-04                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04  
Study Type: CHRONIC                                             ISOBUTENE                                         Date: 09/14/00    
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 13:41:05    
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 5| 6| 3| 3| 6| 7| 7| 6| 2| 6| 7| 7| 7| 7| 5|            |
                             DAY ON TEST   | 3| 3| 3| 3| 3| 3| 0| 3| 3| 3| 4| 7| 3| 8| 3| 3| 3| 9| 5| 3| 3| 3| 3| 3| 0|            |
                                           | 3| 4| 4| 4| 4| 4| 6| 4| 4| 4| 7| 0| 0| 6| 9| 4| 4| 5| 1| 1| 4| 4| 4| 4| 8|            |
 __________________________________________|__________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   B6C3F1 MICE MALE                        | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6|     A      |
    8000 PPM                               | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|     L      |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 _____________________________________________________________________________________________________________________|____________|
 RESPIRATORY SYSTEM - cont                 |                                                                          |            |
                                           |                                                                          |            |
      Lymphoma Malignant                   |                                                                          |          1 |
                                           |__________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
                                           |__________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Eye                                     |                         +                                            +   |   2        |
                                           |__________________________________________________________________________|____________|
   Harderian Gland                         |                                                                   +  +   |   4        |
      Adenoma                              |                                                                          |          2 |
      Carcinoma                            |                                                                   X  X   |          2 |
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |__________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                           |__________________________________________________________________________|____________|
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +|  46        |
 __________________________________________________________________________________________________________________________________ 
 SYSTEMIC LESIONS                          |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Histiocytic Sarcoma                  |                                                                          |          1 |
      Lymphoma Malignant                   |          X                                                               |          5 |
 __________________________________________________________________________________________________________________________________ 
                                                                                                                                    
                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  87                                                               
                                                                                                                                   
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                                  ----------              END OF REPORT             ----------                                      
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