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TDMS Study 60968-02 Pathology Tables

NTP Experiment-Test: 60968-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 03/17/97
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 18:22:07




       Facility:  Battelle Northwest

       Chemical CAS #:  0078-84-2

       Lock Date:  05/12/94

       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: 60968-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 03/17/97  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 18:22:07  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 7| 7| 7| 7| 5| 7| 6| 6| 6| 7| 7| 6| 7| 7| 0| 7| 0| 7| 7| 7| 5| 7|             
                             DAY ON TEST   | 3| 3| 0| 3| 3| 3| 0| 9| 3| 4| 2| 4| 3| 3| 9| 3| 2| 7| 3| 6| 3| 3| 3| 8| 3|             
                                           | 6| 6| 1| 6| 6| 6| 1| 6| 5| 6| 3| 6| 5| 7| 1| 7| 3| 6| 7| 9| 7| 7| 5| 3| 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                             | +  +  +  +  M  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  A  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  A  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +|             
      Hemangiosarcoma                      |                                                                   X      |             
      Hepatocellular Carcinoma             |                                     X                       X        X  X|             
      Hepatocellular Adenoma               |                                  X                                   X  X|             
      Hepatocellular Adenoma, Multiple     |          X                          X                                    |             
      Hepatocholangiocarcinoma             |                      X           X                                       |             
      Histiocytic Sarcoma                  |                                                       X                  |             
      Lymphoma Malignant                   |          X                                                               |             
                                            __________________________________________________________________________|             
   Mesentery                               |                      +  +        +  +                                   +|             
      Hemangiosarcoma                      |                                     X                                    |             
      Hepatocholangiocarcinoma, Metastatic,|                                                                          |             
           Liver                           |                      X           X                                       |             
                                            __________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hepatocholangiocarcinoma, Metastatic,|                                                                          |             
           Liver                           |                      X                                                   |             
      Histiocytic Sarcoma                  |                                                       X                  |             
      Lymphoma Malignant                   |                                                                          |             
                                            __________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                                                                         X|             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hepatocholangiocarcinoma, Metastatic,|                                                                          |             
           Liver                           |                      X                                                   |             
      Histiocytic Sarcoma                  |                                                       X                  |             
      Lymphoma Malignant                   |                                                                         X|             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +|             
      Histiocytic Sarcoma                  |                                                       X                  |             
      Lymphoma Malignant                   |                                                                         X|             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Histiocytic Sarcoma                  |                                                       X                  |             
      Lymphoma Malignant                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             

                                                             Page   2                                                               
NTP Experiment-Test: 60968-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 03/17/97  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 18:22:07  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 7| 7| 7| 7| 5| 7| 6| 6| 6| 7| 7| 6| 7| 7| 0| 7| 0| 7| 7| 7| 5| 7|             
                             DAY ON TEST   | 3| 3| 0| 3| 3| 3| 0| 9| 3| 4| 2| 4| 3| 3| 9| 3| 2| 7| 3| 6| 3| 3| 3| 8| 3|             
                                           | 6| 6| 1| 6| 6| 6| 1| 6| 5| 6| 3| 6| 5| 7| 1| 7| 3| 6| 7| 9| 7| 7| 5| 3| 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|             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM - cont                   |                                                                          |             
                                           |                                                                          |             
      Hepatocholangiocarcinoma, Metastatic,|                                                                          |             
           Liver                           |                      X                                                   |             
      Lymphoma Malignant                   |    X                                                                     |             
                                            __________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Pheochromocytoma Benign              |                                                                          |             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Adenoma                              |                                                                          |             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       | +  +  +  M  I  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Pars Distalis, Adenoma               |    X           X                 X           X        X                  |             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Follicular Cell, Adenoma             | X                                                                        |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Clitoral Gland                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  M|             
                                            __________________________________________________________________________|             
   Ovary                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cystadenoma                          |    X                                                                     |             
      Histiocytic Sarcoma                  |                                                       X                  |             
      Lymphoma Malignant                   |                                                                          |             
      Teratoma Benign                      |                                                                          |             
      Teratoma Malignant                   |                                                    X                     |             
      Tubulostromal Adenoma                |    X                                                                     |             
      Yolk Sac Carcinoma                   |                                                 X                        |             
                                            __________________________________________________________________________|             
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Histiocytic Sarcoma                  |                                                       X                  |             
      Lymphoma Malignant                   |                                                                          |             
      Polyp Stromal                        |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Histiocytic Sarcoma                  |                                                       X                  |             
      Lymphoma Malignant                   |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node                              |    +                                                  +                 +|             
      Lymphoma Malignant                   |                                                                          |             
      Iliac, Histiocytic Sarcoma           |                                                       X                  |             
      Iliac, Lymphoma Malignant            |                                                                         X|             
      Renal, Histiocytic Sarcoma           |                                                       X                  |             
      Renal, Lymphoma Malignant            |    X                                                                    X|             
                                            __________________________________________________________________________|             
   Lymph Node, Bronchial                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  M  +  M  M  +  +  +|             
      Lymphoma Malignant                   |    X                                                                    X|             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  | M  +  +  +  +  +  M  M  +  +  +  +  +  M  +  M  +  +  +  +  +  M  +  +  +|             
 _____________________________________________________________________________________________________________________|             

                                                             Page   3                                                               
NTP Experiment-Test: 60968-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 03/17/97  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 18:22:07  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 7| 7| 7| 7| 5| 7| 6| 6| 6| 7| 7| 6| 7| 7| 0| 7| 0| 7| 7| 7| 5| 7|             
                             DAY ON TEST   | 3| 3| 0| 3| 3| 3| 0| 9| 3| 4| 2| 4| 3| 3| 9| 3| 2| 7| 3| 6| 3| 3| 3| 8| 3|             
                                           | 6| 6| 1| 6| 6| 6| 1| 6| 5| 6| 3| 6| 5| 7| 1| 7| 3| 6| 7| 9| 7| 7| 5| 3| 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                  |                                                       X                  |             
      Lymphoma Malignant                   |    X                                                                    X|             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  I  +  +  +  A  +  +  +  +  +  +  +  +  +  +|             
      Hepatocholangiocarcinoma, Metastatic,|                                                                          |             
           Liver                           |                      X                                                   |             
      Histiocytic Sarcoma                  |                                                       X                  |             
      Lymphoma Malignant                   |    X                                                                    X|             
                                            __________________________________________________________________________|             
   Lymph Node, Mediastinal                 | +  +  M  +  +  +  +  +  M  +  +  +  +  +  M  M  +  +  +  M  +  +  M  +  +|             
      Hepatocholangiocarcinoma, Metastatic,|                                                                          |             
           Liver                           |                      X           X                                       |             
      Histiocytic Sarcoma                  |                                                       X                  |             
      Lymphoma Malignant                   |    X                                                                     |             
                                            __________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hepatocholangiocarcinoma, Metastatic,|                                                                          |             
           Liver                           |                      X           X                                       |             
      Lymphoma Malignant                   | X  X     X                                                              X|             
                                            __________________________________________________________________________|             
   Thymus                                  | +  +  +  +  +  +  +  M  +  +  +  M  +  +  +  +  M  +  +  +  +  +  +  M  +|             
      Histiocytic Sarcoma                  |                                                       X                  |             
      Lymphoma Malignant                   |                                                                         X|             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Carcinoma                            |                                                             X            |             
                                            __________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Histiocytic Sarcoma                  |                                                       X                  |             
      Lymphoma Malignant                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Larynx                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Alveolar/Bronchiolar Carcinoma       |                                                                          |             
      Hepatocellular Carcinoma, Metastatic,|                                                                          |             
           Liver                           |                                                             X            |             
      Hepatocholangiocarcinoma, Metastatic,|                                                                          |             
           Liver                           |                      X           X                                       |             
      Histiocytic Sarcoma                  |                                                       X                  |             
      Lymphoma Malignant                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             

                                                             Page   4                                                               
NTP Experiment-Test: 60968-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 03/17/97  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 18:22:07  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 7| 7| 7| 7| 5| 7| 6| 6| 6| 7| 7| 6| 7| 7| 0| 7| 0| 7| 7| 7| 5| 7|             
                             DAY ON TEST   | 3| 3| 0| 3| 3| 3| 0| 9| 3| 4| 2| 4| 3| 3| 9| 3| 2| 7| 3| 6| 3| 3| 3| 8| 3|             
                                           | 6| 6| 1| 6| 6| 6| 1| 6| 5| 6| 3| 6| 5| 7| 1| 7| 3| 6| 7| 9| 7| 7| 5| 3| 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                 |                                                                          |             
                                           |                                                                          |             
      Mediastinum,                         |                                                                          |             
          Hepatocholangiocarcinoma,        |                                                                          |             
          Metastatic, Liver                |                      X                                                   |             
      Mediastinum, Lymphoma Malignant      |          X                                                               |             
                                            __________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Histiocytic Sarcoma                  |                                                       X                  |             
      Lymphoma Malignant                   |                                                                          |             
                                            __________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Harderian Gland                         |                                                                +         |             
      Adenoma                              |                                                                X         |             
      Carcinoma                            |                                                                          |             
      Lymphoma Malignant                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hepatocholangiocarcinoma, Metastatic,|                                                                          |             
           Liver                           |                      X                                                   |             
      Histiocytic Sarcoma                  |                                                       X                  |             
      Lymphoma Malignant                   |                                                                          |             
                                            __________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +|             
      Histiocytic Sarcoma                  |                                                       X                  |             
      Lymphoma Malignant                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 SYSTEMIC LESIONS                          |                                                                          |             
                                            __________________________________________________________________________|             
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Histiocytic Sarcoma                  |                                                       X                  |             
      Lymphoma Malignant                   | X  X     X                                                              X|             
 _____________________________________________________________________________________________________________________|             

                                                             Page   5                                                               
NTP Experiment-Test: 60968-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 03/17/97  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 18:22:07  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 6| 7| 7| 7| 7| 7| 6| 6| 5| 7| 7| 7| 5| 6| 7| 7| 7| 7| 7| 6| 7| 7| 6| 3| 7|            |
                             DAY ON TEST   | 3| 3| 3| 3| 3| 0| 5| 3| 3| 3| 3| 3| 4| 8| 3| 3| 3| 3| 3| 1| 3| 3| 9| 4| 1|            |
                                           | 7| 6| 5| 5| 5| 0| 7| 9| 3| 7| 7| 7| 3| 6| 5| 6| 6| 6| 7| 1| 6| 6| 5| 4| 2|            |
 _____________________________________________________________________________________________________________________|     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                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Gallbladder                             | +  +  +  +  +  +  +  +  +  +  +  M  A  +  +  +  +  +  +  +  +  +  +  +  +|  46        |
      Lymphoma Malignant                   |                                                          X               |          1 |
                                            __________________________________________________________________________|____________|
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                            __________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +|  47        |
                                            __________________________________________________________________________|____________|
   Intestine Small, Jejunum                | A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  47        |
                                            __________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                            __________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Hemangiosarcoma                      |                                                                          |          1 |
      Hepatocellular Carcinoma             | X                                   X                                    |          6 |
      Hepatocellular Adenoma               |                            X                                X     X      |          6 |
      Hepatocellular Adenoma, Multiple     |                X                                                         |          3 |
      Hepatocholangiocarcinoma             |                                                                          |          2 |
      Histiocytic Sarcoma                  |                                                                          |          1 |
      Lymphoma Malignant                   |                X        X                    X           X        X      |          6 |
                                            __________________________________________________________________________|____________|
   Mesentery                               |       +     +                                                     +      |   8        |
      Hemangiosarcoma                      |                                                                          |          1 |
      Hepatocholangiocarcinoma, Metastatic,|                                                                          |            |
           Liver                           |                                                                          |          2 |
                                            __________________________________________________________________________|____________|
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hepatocholangiocarcinoma, Metastatic,|                                                                          |            |
           Liver                           |                                                                          |          1 |
      Histiocytic Sarcoma                  |                                                                          |          1 |
      Lymphoma Malignant                   |                         X                                X               |          2 |
                                            __________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Lymphoma Malignant                   |                X                                         X               |          3 |
                                            __________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hepatocholangiocarcinoma, Metastatic,|                                                                          |            |
           Liver                           |                                                                          |          1 |
      Histiocytic Sarcoma                  |                                                                          |          1 |
      Lymphoma Malignant                   |                         X                                X               |          3 |
                                            __________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Histiocytic Sarcoma                  |                                                                          |          1 |
      Lymphoma Malignant                   |                                                          X               |          2 |
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  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   6                                                               
NTP Experiment-Test: 60968-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 03/17/97  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 18:22:07  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 6| 7| 7| 7| 7| 7| 6| 6| 5| 7| 7| 7| 5| 6| 7| 7| 7| 7| 7| 6| 7| 7| 6| 3| 7|            |
                             DAY ON TEST   | 3| 3| 3| 3| 3| 0| 5| 3| 3| 3| 3| 3| 4| 8| 3| 3| 3| 3| 3| 1| 3| 3| 9| 4| 1|            |
                                           | 7| 6| 5| 5| 5| 0| 7| 9| 3| 7| 7| 7| 3| 6| 5| 6| 6| 6| 7| 1| 6| 6| 5| 4| 2|            |
 _____________________________________________________________________________________________________________________|     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|            |
 __________________________________________________________________________________________________________________________________ 
 CARDIOVASCULAR SYSTEM - cont              |                                                                          |            |
                                           |                                                                          |            |
      Histiocytic Sarcoma                  |                                                                          |          1 |
      Lymphoma Malignant                   |                         X                                                |          1 |
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hepatocholangiocarcinoma, Metastatic,|                                                                          |            |
           Liver                           |                                                                          |          1 |
      Lymphoma Malignant                   |                         X                                X               |          3 |
                                            __________________________________________________________________________|____________|
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Pheochromocytoma Benign              |                                           X                              |          1 |
                                            __________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Adenoma                              |                      X                                                   |          1 |
                                            __________________________________________________________________________|____________|
   Parathyroid Gland                       | +  +  +  +  +  +  +  +  M  +  +  +  +  M  +  +  M  +  +  +  +  +  +  +  +|  44        |
                                            __________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Pars Distalis, Adenoma               |             X           X  X           X           X                     |         10 |
                                            __________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Follicular Cell, Adenoma             |    X  X                                                                  |          3 |
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
                                           |                                                                          |            |
    None                                   |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Clitoral Gland                          | +  +  +  +  +  +  M  +  M  +  +  +  +  I  +  M  +  +  +  +  +  +  +  +  +|  44        |
                                            __________________________________________________________________________|____________|
   Ovary                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Cystadenoma                          |                                                                          |          1 |
      Histiocytic Sarcoma                  |                                                                          |          1 |
      Lymphoma Malignant                   |                X        X                                X        X      |          4 |
      Teratoma Benign                      |                                                 X                        |          1 |
      Teratoma Malignant                   |                                                                          |          1 |
      Tubulostromal Adenoma                |                                                                          |          1 |
      Yolk Sac Carcinoma                   |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Histiocytic Sarcoma                  |                                                                          |          1 |
      Lymphoma Malignant                   |                         X                                X               |          2 |
      Polyp Stromal                        |                                                       X              X   |          2 |
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      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   7                                                               
NTP Experiment-Test: 60968-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 03/17/97  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 18:22:07  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 6| 7| 7| 7| 7| 7| 6| 6| 5| 7| 7| 7| 5| 6| 7| 7| 7| 7| 7| 6| 7| 7| 6| 3| 7|            |
                             DAY ON TEST   | 3| 3| 3| 3| 3| 0| 5| 3| 3| 3| 3| 3| 4| 8| 3| 3| 3| 3| 3| 1| 3| 3| 9| 4| 1|            |
                                           | 7| 6| 5| 5| 5| 0| 7| 9| 3| 7| 7| 7| 3| 6| 5| 6| 6| 6| 7| 1| 6| 6| 5| 4| 2|            |
 _____________________________________________________________________________________________________________________|     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               |                                                                          |            |
                                           |                                                                          |            |
      Lymphoma Malignant                   |                                                          X               |          1 |
                                            __________________________________________________________________________|____________|
   Lymph Node                              |                         +                                +               |   5        |
      Lymphoma Malignant                   |                                                          X               |          1 |
      Iliac, Histiocytic Sarcoma           |                                                                          |          1 |
      Iliac, Lymphoma Malignant            |                         X                                                |          2 |
      Renal, Histiocytic Sarcoma           |                                                                          |          1 |
      Renal, Lymphoma Malignant            |                                                                          |          2 |
                                            __________________________________________________________________________|____________|
   Lymph Node, Bronchial                   | +  M  +  +  +  +  +  M  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  M  +|  42        |
      Lymphoma Malignant                   |                X        X     X              X           X        X      |          8 |
                                            __________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | +  M  +  +  M  +  +  M  M  M  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +|  38        |
      Histiocytic Sarcoma                  |                                                                          |          1 |
      Lymphoma Malignant                   |                X                                         X     X  X      |          6 |
                                            __________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
      Hepatocholangiocarcinoma, Metastatic,|                                                                          |            |
           Liver                           |                                                                          |          1 |
      Histiocytic Sarcoma                  |                                                                          |          1 |
      Lymphoma Malignant                   |                X        X     X              X           X     X         |          8 |
                                            __________________________________________________________________________|____________|
   Lymph Node, Mediastinal                 | +  +  +  +  +  M  +  M  M  M  +  +  M  +  +  +  +  M  +  +  +  +  +  +  +|  38        |
      Hepatocholangiocarcinoma, Metastatic,|                                                                          |            |
           Liver                           |                                                                          |          2 |
      Histiocytic Sarcoma                  |                                                                          |          1 |
      Lymphoma Malignant                   |                               X              X           X     X  X      |          6 |
                                            __________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hepatocholangiocarcinoma, Metastatic,|                                                                          |            |
           Liver                           |                                                                          |          2 |
      Lymphoma Malignant                   |          X     X        X     X              X           X     X  X      |         12 |
                                            __________________________________________________________________________|____________|
   Thymus                                  | +  M  +  +  +  +  +  M  M  +  +  +  +  +  M  +  +  +  +  +  +  +  +  M  +|  41        |
      Histiocytic Sarcoma                  |                                                                          |          1 |
      Lymphoma Malignant                   |                X                             X           X               |          4 |
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +|  49        |
      Carcinoma                            |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Lymphoma Malignant                   |                X                                         X               |          2 |
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 NERVOUS 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   8                                                               
NTP Experiment-Test: 60968-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 03/17/97  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 18:22:07  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 6| 7| 7| 7| 7| 7| 6| 6| 5| 7| 7| 7| 5| 6| 7| 7| 7| 7| 7| 6| 7| 7| 6| 3| 7|            |
                             DAY ON TEST   | 3| 3| 3| 3| 3| 0| 5| 3| 3| 3| 3| 3| 4| 8| 3| 3| 3| 3| 3| 1| 3| 3| 9| 4| 1|            |
                                           | 7| 6| 5| 5| 5| 0| 7| 9| 3| 7| 7| 7| 3| 6| 5| 6| 6| 6| 7| 1| 6| 6| 5| 4| 2|            |
 _____________________________________________________________________________________________________________________|     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 - cont                     |                                                                          |            |
                                           |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Histiocytic Sarcoma                  |                                                                          |          1 |
      Lymphoma Malignant                   |                         X                                X               |          2 |
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Larynx                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Alveolar/Bronchiolar Carcinoma       |                                     X        X  X                        |          3 |
      Hepatocellular Carcinoma, Metastatic,|                                                                          |            |
           Liver                           |                                     X                                    |          2 |
      Hepatocholangiocarcinoma, Metastatic,|                                                                          |            |
           Liver                           |                                                                          |          2 |
      Histiocytic Sarcoma                  |                                                                          |          1 |
      Lymphoma Malignant                   |                X        X                    X           X     X         |          5 |
      Mediastinum,                         |                                                                          |            |
          Hepatocholangiocarcinoma,        |                                                                          |            |
          Metastatic, Liver                |                                                                          |          1 |
      Mediastinum, Lymphoma Malignant      |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Histiocytic Sarcoma                  |                                                                          |          1 |
      Lymphoma Malignant                   |                                                          X               |          1 |
                                            __________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Harderian Gland                         |                                                    +     +               |   3        |
      Adenoma                              |                                                                          |          1 |
      Carcinoma                            |                                                    X                     |          1 |
      Lymphoma Malignant                   |                                                          X               |          1 |
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hepatocholangiocarcinoma, Metastatic,|                                                                          |            |
           Liver                           |                                                                          |          1 |
      Histiocytic Sarcoma                  |                                                                          |          1 |
      Lymphoma Malignant                   |                         X     X              X           X     X         |          5 |
                                            __________________________________________________________________________|____________|
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Histiocytic Sarcoma                  |                                                                          |          1 |
      Lymphoma Malignant                   |                         X     X                          X               |          3 |
 __________________________________________________________________________________________________________________________________ 
 SYSTEMIC LESIONS                          |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  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   9                                                               
NTP Experiment-Test: 60968-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 03/17/97  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 18:22:07  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 6| 7| 7| 7| 7| 7| 6| 6| 5| 7| 7| 7| 5| 6| 7| 7| 7| 7| 7| 6| 7| 7| 6| 3| 7|            |
                             DAY ON TEST   | 3| 3| 3| 3| 3| 0| 5| 3| 3| 3| 3| 3| 4| 8| 3| 3| 3| 3| 3| 1| 3| 3| 9| 4| 1|            |
                                           | 7| 6| 5| 5| 5| 0| 7| 9| 3| 7| 7| 7| 3| 6| 5| 6| 6| 6| 7| 1| 6| 6| 5| 4| 2|            |
 _____________________________________________________________________________________________________________________|     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|            |
 __________________________________________________________________________________________________________________________________ 
 SYSTEMIC LESIONS - cont                   |                                                                          |            |
                                           |                                                                          |            |
      Histiocytic Sarcoma                  |                                                                          |          1 |
      Lymphoma Malignant                   |          X     X        X     X              X           X     X  X      |         12 |
 __________________________________________________________________________________________________________________________________ 

                         * : 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: 60968-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 03/17/97  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 18:22:07  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 0| 7| 7| 7| 7| 7| 6| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7| 6| 6| 7| 7| 7| 7|             
                             DAY ON TEST   | 3| 9| 0| 3| 3| 3| 3| 1| 3| 3| 8| 1| 3| 3| 3| 3| 3| 3| 3| 0| 9| 3| 3| 3| 3|             
                                           | 7| 3| 2| 6| 6| 1| 7| 1| 6| 6| 1| 2| 7| 6| 6| 7| 6| 6| 5| 3| 1| 5| 7| 5| 7|             
 _____________________________________________________________________________________________________________________|             
                                           | 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                             | M  A  +  +  +  A  +  A  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  +  +  A  +  A  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +|             
      Leiomyoma                            |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               | +  A  +  +  +  A  +  A  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +|             
      Polyp Adenomatous                    |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  +  A  +  A  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +|             
      Lymphoma Malignant                   |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  +  A  +  A  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +|             
      Lymphoma Malignant                   |                                                                          |             
                                            __________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemangiosarcoma                      |       X                                                                  |             
      Hepatocellular Carcinoma             |       X                       X  X                 X  X                  |             
      Hepatocellular Carcinoma, Multiple   |                                                                          |             
      Hepatocellular Adenoma               | X        X  X                                X                    X      |             
      Hepatocholangiocarcinoma             |                                                                          |             
      Lymphoma Malignant                   |                         X        X                             X         |             
                                            __________________________________________________________________________|             
   Mesentery                               |                         +                                               +|             
                                            __________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                                                                          |             
                                            __________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                                                                          |             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                                                                          |             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Adenoma                              |                                                                          |             
      Capsule, Adenoma                     |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Pheochromocytoma Benign              |                                                             X            |             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Adenoma                              |                X                                                         |             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       | +  +  M  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  M  +  +  M  +  +|             
                                            __________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Pars Distalis, Adenoma               |             X           X  X  X           X  X        X              X   |             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             

                                                             Page  11                                                               
NTP Experiment-Test: 60968-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 03/17/97  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 18:22:07  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 0| 7| 7| 7| 7| 7| 6| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7| 6| 6| 7| 7| 7| 7|             
                             DAY ON TEST   | 3| 9| 0| 3| 3| 3| 3| 1| 3| 3| 8| 1| 3| 3| 3| 3| 3| 3| 3| 0| 9| 3| 3| 3| 3|             
                                           | 7| 3| 2| 6| 6| 1| 7| 1| 6| 6| 1| 2| 7| 6| 6| 7| 6| 6| 5| 3| 1| 5| 7| 5| 7|             
 _____________________________________________________________________________________________________________________|             
                                           | 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|             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM - cont                   |                                                                          |             
                                           |                                                                          |             
      Follicular Cell, Adenoma             |                                                 X                        |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Clitoral Gland                          | M  +  +  +  +  +  +  +  +  M  +  M  +  +  +  +  +  I  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Ovary                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Choriocarcinoma                      |    X                                                                     |             
      Cystadenocarcinoma                   |                                                                X         |             
      Cystadenoma                          |                                                    X                    X|             
      Luteoma                              |                                                                          |             
      Lymphoma Malignant                   |                   X  X           X                                       |             
                                            __________________________________________________________________________|             
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                                                                          |             
      Polyp Stromal                        |                                           X                              |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemangiosarcoma                      |                                                                          |             
      Lymphoma Malignant                   |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node                              |                                                                          |             
      Lymphoma Malignant                   |                                                                          |             
      Iliac, Lymphoma Malignant            |                                                                          |             
      Pancreatic, Lymphoma Malignant       |                                                                          |             
      Renal, Hemangiosarcoma               |                                                                          |             
      Renal, Lymphoma Malignant            |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node, Bronchial                   | M  M  +  M  M  M  +  +  +  +  +  M  +  M  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                      X                                         X         |             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  M  +  +  M  +  +  +  M  +  M  +  +  +  +  +  +  +  +  M  +  M  M  +|             
      Lymphoma Malignant                   |                                                                X         |             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +|             
      Lymphoma Malignant                   |                      X     X     X                             X         |             
                                            __________________________________________________________________________|             
   Lymph Node, Mediastinal                 | M  +  M  +  M  +  +  +  +  +  +  +  M  +  M  +  +  +  +  +  +  +  M  M  M|             
      Lymphoma Malignant                   |                      X           X                             X         |             
                                            __________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemangiosarcoma                      |                                                                          |             
      Lymphoma Malignant                   |          X        X     X  X     X                             X         |             
                                            __________________________________________________________________________|             
   Thymus                                  | +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  M  +  +|             
      Lymphoma Malignant                   |                   X                                                      |             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Carcinoma                            |                                                                          |             
 _____________________________________________________________________________________________________________________|             

                                                             Page  12                                                               
NTP Experiment-Test: 60968-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 03/17/97  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 18:22:07  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 0| 7| 7| 7| 7| 7| 6| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7| 6| 6| 7| 7| 7| 7|             
                             DAY ON TEST   | 3| 9| 0| 3| 3| 3| 3| 1| 3| 3| 8| 1| 3| 3| 3| 3| 3| 3| 3| 0| 9| 3| 3| 3| 3|             
                                           | 7| 3| 2| 6| 6| 1| 7| 1| 6| 6| 1| 2| 7| 6| 6| 7| 6| 6| 5| 3| 1| 5| 7| 5| 7|             
 _____________________________________________________________________________________________________________________|             
                                           | 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|             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM - cont               |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Subcutaneous Tissue, Fibrosarcoma    |                                                                          |             
      Subcutaneous Tissue, Hemangiosarcoma |                                  X                                       |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Skeletal Muscle                         |                                                          +               |             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Larynx                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Alveolar/Bronchiolar Adenoma         |                                                                          |             
      Carcinoma, Metastatic, Mammary Gland |                                                                          |             
      Hepatocellular Carcinoma, Metastatic,|                                                                          |             
           Liver                           |                                                                          |             
      Hepatocholangiocarcinoma, Metastatic,|                                                                          |             
           Liver                           |                                                                          |             
      Lymphoma Malignant                   |                                  X                                       |             
                                            __________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Harderian Gland                         |                   +                                         +            |             
      Adenoma                              |                   X                                         X            |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                                  X                                       |             
                                            __________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SYSTEMIC LESIONS                          |                                                                          |             
                                            __________________________________________________________________________|             
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |          X        X  X  X  X     X                             X         |             
 _____________________________________________________________________________________________________________________|             

                                                             Page  13                                                               
NTP Experiment-Test: 60968-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 03/17/97  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 18:22:07  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 5| 6| 7| 7| 6| 7| 6| 6| 5| 7| 7| 6| 7| 7| 5| 7| 7| 7| 7| 7| 6| 7| 6|            |
                             DAY ON TEST   | 3| 3| 9| 1| 3| 3| 2| 3| 3| 6| 2| 3| 3| 9| 3| 3| 4| 3| 3| 3| 3| 3| 8| 3| 2|            |
                                           | 5| 6| 5| 1| 6| 6| 1| 7| 6| 3| 7| 5| 7| 5| 7| 6| 6| 7| 7| 7| 5| 5| 6| 7| 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 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                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +|  44        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +|  48        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +|  46        |
      Leiomyoma                            |                                                                   X      |          1 |
                                            __________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +|  45        |
      Polyp Adenomatous                    |                         X                                                |          1 |
                                            __________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +|  46        |
      Lymphoma Malignant                   |                      X     X                                X            |          3 |
                                            __________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +|  46        |
      Lymphoma Malignant                   |                            X                                             |          1 |
                                            __________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Hemangiosarcoma                      |                                                                          |          1 |
      Hepatocellular Carcinoma             |                   X           X                 X                        |          8 |
      Hepatocellular Carcinoma, Multiple   |                                        X                                 |          1 |
      Hepatocellular Adenoma               |             X           X  X     X     X           X        X            |         12 |
      Hepatocholangiocarcinoma             |    X                                                                     |          1 |
      Lymphoma Malignant                   |          X                 X                                             |          5 |
                                            __________________________________________________________________________|____________|
   Mesentery                               |                                                                          |   2        |
                                            __________________________________________________________________________|____________|
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Lymphoma Malignant                   |                            X                                             |          1 |
                                            __________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Lymphoma Malignant                   |                            X                                             |          1 |
                                            __________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Lymphoma Malignant                   |          X                                                               |          1 |
                                            __________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Lymphoma Malignant                   |          X                 X                                             |          2 |
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Adenoma                              |                                                          X               |          1 |
      Capsule, Adenoma                     |                                     X                                    |          1 |
                                            __________________________________________________________________________|____________|
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Pheochromocytoma Benign              |                                                                      X   |          2 |
                                            __________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  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  14                                                               
NTP Experiment-Test: 60968-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 03/17/97  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 18:22:07  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 5| 6| 7| 7| 6| 7| 6| 6| 5| 7| 7| 6| 7| 7| 5| 7| 7| 7| 7| 7| 6| 7| 6|            |
                             DAY ON TEST   | 3| 3| 9| 1| 3| 3| 2| 3| 3| 6| 2| 3| 3| 9| 3| 3| 4| 3| 3| 3| 3| 3| 8| 3| 2|            |
                                           | 5| 6| 5| 1| 6| 6| 1| 7| 6| 3| 7| 5| 7| 5| 7| 6| 6| 7| 7| 7| 5| 5| 6| 7| 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 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                   |                                                                          |            |
                                           |                                                                          |            |
      Adenoma                              |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Parathyroid Gland                       | +  +  +  +  +  +  M  +  +  M  +  +  +  +  +  M  +  +  +  M  +  M  +  +  M|  40        |
                                            __________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +|  49        |
      Pars Distalis, Adenoma               |             X                                                            |          9 |
                                            __________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Follicular Cell, Adenoma             |                                                                          |          1 |
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
                                           |                                                                          |            |
    None                                   |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Clitoral Gland                          | +  +  +  M  M  +  I  +  +  +  +  +  +  M  +  M  +  +  +  +  +  +  M  +  M|  39        |
                                            __________________________________________________________________________|____________|
   Ovary                                   | +  +  +  +  +  +  +  +  I  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Choriocarcinoma                      |                                                                          |          1 |
      Cystadenocarcinoma                   |                                                          X               |          2 |
      Cystadenoma                          |                      X                       X                          X|          5 |
      Luteoma                              |                                                                X         |          1 |
      Lymphoma Malignant                   |          X                 X                                             |          5 |
                                            __________________________________________________________________________|____________|
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Lymphoma Malignant                   |                            X                                             |          1 |
      Polyp Stromal                        |                X                                                         |          2 |
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hemangiosarcoma                      |                                                                         X|          1 |
      Lymphoma Malignant                   |          X                                X                              |          2 |
                                            __________________________________________________________________________|____________|
   Lymph Node                              |       +  +                 +     +                          +            |   5        |
      Lymphoma Malignant                   |                            X                                             |          1 |
      Iliac, Lymphoma Malignant            |          X                 X     X                                       |          3 |
      Pancreatic, Lymphoma Malignant       |                                                             X            |          1 |
      Renal, Hemangiosarcoma               |       X                                                                  |          1 |
      Renal, Lymphoma Malignant            |                            X     X                          X            |          3 |
                                            __________________________________________________________________________|____________|
   Lymph Node, Bronchial                   | M  +  +  +  +  M  M  +  M  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  38        |
      Lymphoma Malignant                   |          X                 X     X                                       |          5 |
                                            __________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | +  +  +  +  +  M  +  M  +  +  +  +  +  +  +  +  M  +  +  M  M  +  +  +  +|  38        |
      Lymphoma Malignant                   |          X                 X                                             |          3 |
                                            __________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Lymphoma Malignant                   |          X           X     X              X                 X            |          9 |
                                            __________________________________________________________________________|____________|
   Lymph Node, Mediastinal                 | M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  M  +  +  +  M  +  +|  38        |
 __________________________________________________________________________________________________________________________________ 

                         * : 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  15                                                               
NTP Experiment-Test: 60968-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 03/17/97  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 18:22:07  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 5| 6| 7| 7| 6| 7| 6| 6| 5| 7| 7| 6| 7| 7| 5| 7| 7| 7| 7| 7| 6| 7| 6|            |
                             DAY ON TEST   | 3| 3| 9| 1| 3| 3| 2| 3| 3| 6| 2| 3| 3| 9| 3| 3| 4| 3| 3| 3| 3| 3| 8| 3| 2|            |
                                           | 5| 6| 5| 1| 6| 6| 1| 7| 6| 3| 7| 5| 7| 5| 7| 6| 6| 7| 7| 7| 5| 5| 6| 7| 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 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               |                                                                          |            |
                                           |                                                                          |            |
      Lymphoma Malignant                   |          X                 X     X                                       |          6 |
                                            __________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Hemangiosarcoma                      |                                                                         X|          1 |
      Lymphoma Malignant                   |          X           X     X     X        X                              |         11 |
                                            __________________________________________________________________________|____________|
   Thymus                                  | +  +  M  +  +  +  M  +  M  +  M  +  +  +  +  +  M  +  +  +  +  +  +  +  +|  43        |
      Lymphoma Malignant                   |          X                 X                                             |          3 |
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Carcinoma                            |                                                                   X      |          1 |
                                            __________________________________________________________________________|____________|
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Subcutaneous Tissue, Fibrosarcoma    |                         X                                                |          1 |
      Subcutaneous Tissue, Hemangiosarcoma |                                                                         X|          2 |
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Skeletal Muscle                         |                                                                          |   1        |
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Lymphoma Malignant                   |                            X                                             |          1 |
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Larynx                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Alveolar/Bronchiolar Adenoma         |                                           X                              |          1 |
      Carcinoma, Metastatic, Mammary Gland |                                                                   X      |          1 |
      Hepatocellular Carcinoma, Metastatic,|                                                                          |            |
           Liver                           |                               X                 X                        |          2 |
      Hepatocholangiocarcinoma, Metastatic,|                                                                          |            |
           Liver                           |    X                                                                     |          1 |
      Lymphoma Malignant                   |          X                 X                                             |          3 |
                                            __________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Harderian Gland                         |                                                             +     +      |   4        |
      Adenoma                              |                                                             X     X      |          4 |
 _____________________________________________________________________________________________________________________|            |
 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  16                                                               
NTP Experiment-Test: 60968-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 03/17/97  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 18:22:07  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 5| 6| 7| 7| 6| 7| 6| 6| 5| 7| 7| 6| 7| 7| 5| 7| 7| 7| 7| 7| 6| 7| 6|            |
                             DAY ON TEST   | 3| 3| 9| 1| 3| 3| 2| 3| 3| 6| 2| 3| 3| 9| 3| 3| 4| 3| 3| 3| 3| 3| 8| 3| 2|            |
                                           | 5| 6| 5| 1| 6| 6| 1| 7| 6| 3| 7| 5| 7| 5| 7| 6| 6| 7| 7| 7| 5| 5| 6| 7| 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 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|            |
 __________________________________________________________________________________________________________________________________ 
 URINARY SYSTEM - cont                     |                                                                          |            |
                                           |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Lymphoma Malignant                   |          X                 X              X                 X            |          5 |
                                            __________________________________________________________________________|____________|
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
 __________________________________________________________________________________________________________________________________ 
 SYSTEMIC LESIONS                          |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Lymphoma Malignant                   |          X           X     X     X        X                 X            |         13 |
 __________________________________________________________________________________________________________________________________ 

                         * : 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  17                                                               
NTP Experiment-Test: 60968-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 03/17/97  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 18:22:07  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 5| 7| 7| 7| 7| 6| 6| 5| 6| 7| 7| 7| 7| 7| 7| 7| 7| 6| 5| 6| 7| 7| 7| 5| 7|             
                             DAY ON TEST   | 8| 3| 3| 3| 3| 6| 1| 7| 7| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 0| 3| 3| 3| 3| 3|             
                                           | 1| 7| 6| 6| 6| 5| 1| 7| 4| 6| 6| 6| 7| 6| 6| 7| 5| 3| 7| 9| 6| 5| 6| 7| 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   | 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|             
    1000 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  +  +  +  +  A  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                                                       X                  |             
                                            __________________________________________________________________________|             
   Intestine Large, Colon                  | A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Rectum                 | A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                                                          X               |             
                                            __________________________________________________________________________|             
   Intestine Large, Cecum                  | A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                                                          X               |             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               | A  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                | A  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Carcinoma                            |                                                                          |             
      Lymphoma Malignant                   |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  | A  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                                                                          |             
                                            __________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hepatocellular Carcinoma             |                                                                   X      |             
      Hepatocellular Adenoma               | X                                   X  X           X                     |             
      Hepatocellular Adenoma, Multiple     |             X                                                           X|             
      Histiocytic Sarcoma                  | X                                                                        |             
      Lymphoma Malignant                   |                                  X                    X  X        X      |             
                                            __________________________________________________________________________|             
   Mesentery                               |                         +                                            +   |             
      Histiocytic Sarcoma                  |                         X                                                |             
      Leiomyosarcoma, Metastatic, Uterus   |                                                                          |             
      Lymphoma Malignant                   |                                                                          |             
                                            __________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Carcinoma                            |                                                                      X   |             
      Hemangiosarcoma                      |                                                                          |             
      Histiocytic Sarcoma                  |                         X                                                |             
      Lymphoma Malignant                   |                                                       X  X               |             
                                            __________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                                                       X  X               |             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Histiocytic Sarcoma                  |                         X                                                |             
      Lymphoma Malignant                   |                                  X                    X  X               |             
      Squamous Cell Papilloma              |                                  X                                       |             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                                                       X  X               |             
                                            __________________________________________________________________________|             
   Tongue                                  |                +                                                         |             
      Squamous Cell Carcinoma              |                X                                                         |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                                  X                                       |             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
 _____________________________________________________________________________________________________________________|             

                                                             Page  18                                                               
NTP Experiment-Test: 60968-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 03/17/97  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 18:22:07  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 5| 7| 7| 7| 7| 6| 6| 5| 6| 7| 7| 7| 7| 7| 7| 7| 7| 6| 5| 6| 7| 7| 7| 5| 7|             
                             DAY ON TEST   | 8| 3| 3| 3| 3| 6| 1| 7| 7| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 0| 3| 3| 3| 3| 3|             
                                           | 1| 7| 6| 6| 6| 5| 1| 7| 4| 6| 6| 6| 7| 6| 6| 7| 5| 3| 7| 9| 6| 5| 6| 7| 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   | 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|             
    1000 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                   |                                                                          |             
                                           |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Histiocytic Sarcoma                  |                         X                                                |             
      Lymphoma Malignant                   |                                                       X  X               |             
                                            __________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Adenoma                              |                                                    X                     |             
      Carcinoma                            |                                                                          |             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       | +  +  M  +  +  +  M  +  +  +  +  M  M  +  +  +  +  +  M  M  +  +  +  M  +|             
                                            __________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Pars Distalis, Adenoma               |             X           X                    X                           |             
      Pars Intermedia, Adenoma             |                X                                                         |             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Follicular Cell, Adenoma             |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Clitoral Gland                          | M  +  +  +  +  M  +  +  +  +  +  +  +  +  +  M  +  +  +  +  M  +  +  +  +|             
                                            __________________________________________________________________________|             
   Ovary                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Histiocytic Sarcoma                  | X                                                                        |             
      Luteoma                              |                                              X                           |             
      Lymphoma Malignant                   |                                                       X  X               |             
      Bilateral, Cystadenoma               |    X                                                                     |             
                                            __________________________________________________________________________|             
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Histiocytic Sarcoma                  | X                                X                                       |             
      Leiomyosarcoma                       |                                                                          |             
      Lymphoma Malignant                   |                                                       X  X               |             
      Polyp Stromal                        |                                                                          |             
                                            __________________________________________________________________________|             
   Vagina                                  |                                  +                                       |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemangiosarcoma                      |                                                                          |             
      Lymphoma Malignant                   |                                                       X  X               |             
                                            __________________________________________________________________________|             
   Lymph Node                              | +                                                        +               |             
      Iliac, Histiocytic Sarcoma           | X                                                                        |             
      Iliac, Lymphoma Malignant            |                                                          X               |             
      Renal, Lymphoma Malignant            |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node, Bronchial                   | M  +  +  M  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                            X     X                    X  X               |             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  M  +  +  +  +  +  M  M  M  +  +  +  +  +  +  +  +  +  +  +  +  +  M|             
      Lymphoma Malignant                   |                                  X                    X  X               |             
 _____________________________________________________________________________________________________________________|             

                                                             Page  19                                                               
NTP Experiment-Test: 60968-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 03/17/97  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 18:22:07  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 5| 7| 7| 7| 7| 6| 6| 5| 6| 7| 7| 7| 7| 7| 7| 7| 7| 6| 5| 6| 7| 7| 7| 5| 7|             
                             DAY ON TEST   | 8| 3| 3| 3| 3| 6| 1| 7| 7| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 0| 3| 3| 3| 3| 3|             
                                           | 1| 7| 6| 6| 6| 5| 1| 7| 4| 6| 6| 6| 7| 6| 6| 7| 5| 3| 7| 9| 6| 5| 6| 7| 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   | 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|             
    1000 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               |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  | M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                            X     X           X        X  X               |             
                                            __________________________________________________________________________|             
   Lymph Node, Mediastinal                 | +  M  +  +  +  +  M  M  +  +  +  +  +  +  +  +  +  M  M  +  M  +  +  M  M|             
      Lymphoma Malignant                   |                                  X                       X               |             
                                            __________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemangiosarcoma                      |                                                                          |             
      Lymphoma Malignant                   |                            X     X           X        X  X        X      |             
                                            __________________________________________________________________________|             
   Thymus                                  | M  +  +  +  M  M  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  M  M  +|             
      Lymphoma Malignant                   |                            X     X           X        X  X               |             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Carcinoma                            |                X                                                         |             
                                            __________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                                                          X               |             
      Subcutaneous Tissue, Hemangiosarcoma |                                                                          |             
      Subcutaneous Tissue, Histiocytic     |                                                                          |             
          Sarcoma                          |                         X                                                |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Skeletal Muscle                         |                                                                          |             
      Fibrosarcoma                         |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                                  X           X                           |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Larynx                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                                                          X               |             
                                            __________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Alveolar/Bronchiolar Adenoma         |                                                                          |             
      Alveolar/Bronchiolar Carcinoma       |                                     X                                    |             
      Carcinoma, Metastatic, Harderian     |                                                                          |             
          Gland                            |                                                                          |             
      Carcinoma, Metastatic, Mammary Gland |                                                                          |             
      Hepatocellular Carcinoma, Metastatic,|                                                                          |             
           Liver                           |                                                                          |             
      Histiocytic Sarcoma                  |                         X                                                |             
      Lymphoma Malignant                   |                                  X                    X  X        X      |             
                                            __________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemangioma                           |                                                                          |             
      Histiocytic Sarcoma                  | X                                                                        |             
 _____________________________________________________________________________________________________________________|             

                                                             Page  20                                                               
NTP Experiment-Test: 60968-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 03/17/97  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 18:22:07  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 5| 7| 7| 7| 7| 6| 6| 5| 6| 7| 7| 7| 7| 7| 7| 7| 7| 6| 5| 6| 7| 7| 7| 5| 7|             
                             DAY ON TEST   | 8| 3| 3| 3| 3| 6| 1| 7| 7| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 0| 3| 3| 3| 3| 3|             
                                           | 1| 7| 6| 6| 6| 5| 1| 7| 4| 6| 6| 6| 7| 6| 6| 7| 5| 3| 7| 9| 6| 5| 6| 7| 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   | 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|             
    1000 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                 |                                                                          |             
                                           |                                                                          |             
      Lymphoma Malignant                   |                                                          X               |             
                                            __________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Harderian Gland                         |                                                                          |             
      Adenoma                              |                                                                          |             
      Carcinoma                            |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                                              X        X  X               |             
                                            __________________________________________________________________________|             
   Ureter                                  |          +                                                               |             
      Transitional Epithelium, Papilloma   |          X                                                               |             
                                            __________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Histiocytic Sarcoma                  | X                                                                        |             
      Leiomyosarcoma, Metastatic, Uterus   |                                                                          |             
      Lymphoma Malignant                   |                                                       X  X               |             
 _____________________________________________________________________________________________________________________|             
 SYSTEMIC LESIONS                          |                                                                          |             
                                            __________________________________________________________________________|             
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Histiocytic Sarcoma                  | X                       X        X                                       |             
      Lymphoma Malignant                   |                            X     X           X        X  X        X      |             
 _____________________________________________________________________________________________________________________|             

                                                             Page  21                                                               
NTP Experiment-Test: 60968-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 03/17/97  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 18:22:07  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 6| 6| 7| 7| 7| 6| 7| 7| 5| 7|            |
                             DAY ON TEST   | 3| 3| 3| 3| 1| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 5| 4| 3| 3| 3| 3| 3| 3| 5| 3|            |
                                           | 7| 7| 6| 6| 3| 5| 5| 7| 7| 7| 6| 6| 6| 6| 7| 3| 5| 6| 5| 6| 1| 5| 6| 4| 7|            |
 _____________________________________________________________________________________________________________________|     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      |
    1000 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  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  45        |
      Lymphoma Malignant                   |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Lymphoma Malignant                   |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Lymphoma Malignant                   |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  47        |
                                            __________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
      Carcinoma                            |                      X                                                   |          1 |
      Lymphoma Malignant                   |                         X  X                                             |          2 |
                                            __________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  47        |
      Lymphoma Malignant                   |                   X     X                                                |          2 |
                                            __________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hepatocellular Carcinoma             |             X        X     X                                             |          4 |
      Hepatocellular Adenoma               |                X  X     X        X                             X         |          9 |
      Hepatocellular Adenoma, Multiple     |                                                                          |          2 |
      Histiocytic Sarcoma                  |                                                                          |          1 |
      Lymphoma Malignant                   |                   X     X              X                                 |          7 |
                                            __________________________________________________________________________|____________|
   Mesentery                               |                                              +                       +   |   4        |
      Histiocytic Sarcoma                  |                                                                          |          1 |
      Leiomyosarcoma, Metastatic, Uterus   |                                                                      X   |          1 |
      Lymphoma Malignant                   |                                              X                           |          1 |
                                            __________________________________________________________________________|____________|
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Carcinoma                            |                                                                          |          1 |
      Hemangiosarcoma                      |                                  X                                       |          1 |
      Histiocytic Sarcoma                  |                                                                          |          1 |
      Lymphoma Malignant                   |                                                       X                  |          3 |
                                            __________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Lymphoma Malignant                   |                                                       X                  |          3 |
                                            __________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Histiocytic Sarcoma                  |                                                                          |          1 |
      Lymphoma Malignant                   |                                                                          |          3 |
      Squamous Cell Papilloma              |                                     X                             X      |          3 |
                                            __________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Lymphoma Malignant                   |                                                                          |          2 |
                                            __________________________________________________________________________|____________|
   Tongue                                  |                                                                          |   1        |
      Squamous Cell 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  22                                                               
NTP Experiment-Test: 60968-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 03/17/97  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 18:22:07  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 6| 6| 7| 7| 7| 6| 7| 7| 5| 7|            |
                             DAY ON TEST   | 3| 3| 3| 3| 1| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 5| 4| 3| 3| 3| 3| 3| 3| 5| 3|            |
                                           | 7| 7| 6| 6| 3| 5| 5| 7| 7| 7| 6| 6| 6| 6| 7| 3| 5| 6| 5| 6| 1| 5| 6| 4| 7|            |
 _____________________________________________________________________________________________________________________|     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      |
    1000 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                  |                                                                          |            |
                                           |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Lymphoma Malignant                   |                                                                          |          1 |
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Histiocytic Sarcoma                  |                                                                          |          1 |
      Lymphoma Malignant                   |                                                                          |          2 |
                                            __________________________________________________________________________|____________|
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Adenoma                              |                                                                          |          1 |
      Carcinoma                            |                                  X                          X            |          2 |
                                            __________________________________________________________________________|____________|
   Parathyroid Gland                       | +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  M  +  +|  40        |
                                            __________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Pars Distalis, Adenoma               |             X  X                                         X               |          6 |
      Pars Intermedia, Adenoma             |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Follicular Cell, Adenoma             |       X                                   X                              |          2 |
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
                                           |                                                                          |            |
    None                                   |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Clitoral Gland                          | M  +  +  +  M  M  +  +  +  +  +  +  +  M  +  +  M  +  +  +  M  +  +  +  +|  40        |
                                            __________________________________________________________________________|____________|
   Ovary                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Histiocytic Sarcoma                  |                                                                          |          1 |
      Luteoma                              |                                                                          |          1 |
      Lymphoma Malignant                   |                         X              X     X                           |          5 |
      Bilateral, Cystadenoma               |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Histiocytic Sarcoma                  |                                                                          |          2 |
      Leiomyosarcoma                       |                                                                      X   |          1 |
      Lymphoma Malignant                   |                         X                                                |          3 |
      Polyp Stromal                        |                                           X                              |          1 |
                                            __________________________________________________________________________|____________|
   Vagina                                  |                                                                          |   1        |
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  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  23                                                               
NTP Experiment-Test: 60968-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 03/17/97  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 18:22:07  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 6| 6| 7| 7| 7| 6| 7| 7| 5| 7|            |
                             DAY ON TEST   | 3| 3| 3| 3| 1| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 5| 4| 3| 3| 3| 3| 3| 3| 5| 3|            |
                                           | 7| 7| 6| 6| 3| 5| 5| 7| 7| 7| 6| 6| 6| 6| 7| 3| 5| 6| 5| 6| 1| 5| 6| 4| 7|            |
 _____________________________________________________________________________________________________________________|     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      |
    1000 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               |                                                                          |            |
                                           |                                                                          |            |
      Hemangiosarcoma                      |                               X                                          |          1 |
      Lymphoma Malignant                   |                                        X                                 |          3 |
                                            __________________________________________________________________________|____________|
   Lymph Node                              |       +                 +                                                |   4        |
      Iliac, Histiocytic Sarcoma           |                                                                          |          1 |
      Iliac, Lymphoma Malignant            |                         X                                                |          2 |
      Renal, Lymphoma Malignant            |                         X                                                |          1 |
                                            __________________________________________________________________________|____________|
   Lymph Node, Bronchial                   | +  M  +  +  +  +  +  +  +  +  +  M  +  +  M  +  +  +  +  M  +  +  +  M  +|  42        |
      Lymphoma Malignant                   |                         X                    X        X                  |          7 |
                                            __________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +|  44        |
      Lymphoma Malignant                   |                         X                             X                  |          5 |
                                            __________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  M|  47        |
      Lymphoma Malignant                   |                         X  X                 X                           |          8 |
                                            __________________________________________________________________________|____________|
   Lymph Node, Mediastinal                 | +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  M  M  +|  38        |
      Lymphoma Malignant                   |                   X     X                    X                           |          5 |
                                            __________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hemangiosarcoma                      |       X                                                                  |          1 |
      Lymphoma Malignant                   |                   X     X              X              X                  |         10 |
                                            __________________________________________________________________________|____________|
   Thymus                                  | +  +  +  +  +  +  +  M  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  M  +|  41        |
      Lymphoma Malignant                   |                   X     X  X                          X                  |          9 |
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Carcinoma                            |             X                                                            |          2 |
                                            __________________________________________________________________________|____________|
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Lymphoma Malignant                   |                                                                          |          1 |
      Subcutaneous Tissue, Hemangiosarcoma |                                                          X               |          1 |
      Subcutaneous Tissue, Histiocytic     |                                                                          |            |
          Sarcoma                          |                                                                          |          1 |
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Skeletal Muscle                         |                                                             +            |   1        |
      Fibrosarcoma                         |                                                             X            |          1 |
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Lymphoma Malignant                   |                                                                          |          2 |
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY 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  24                                                               
NTP Experiment-Test: 60968-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 03/17/97  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 18:22:07  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 6| 6| 7| 7| 7| 6| 7| 7| 5| 7|            |
                             DAY ON TEST   | 3| 3| 3| 3| 1| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 5| 4| 3| 3| 3| 3| 3| 3| 5| 3|            |
                                           | 7| 7| 6| 6| 3| 5| 5| 7| 7| 7| 6| 6| 6| 6| 7| 3| 5| 6| 5| 6| 1| 5| 6| 4| 7|            |
 _____________________________________________________________________________________________________________________|     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      |
    1000 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                 |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Larynx                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  I  +  +  +  +  +  +  +  +  +  +|  49        |
      Lymphoma Malignant                   |                                              X                           |          2 |
                                            __________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Alveolar/Bronchiolar Adenoma         |                                                 X                        |          1 |
      Alveolar/Bronchiolar Carcinoma       |                      X                                                   |          2 |
      Carcinoma, Metastatic, Harderian     |                                                                          |            |
          Gland                            |                X                                                         |          1 |
      Carcinoma, Metastatic, Mammary Gland |             X                                                            |          1 |
      Hepatocellular Carcinoma, Metastatic,|                                                                          |            |
           Liver                           |             X                                                            |          1 |
      Histiocytic Sarcoma                  |                                                                          |          1 |
      Lymphoma Malignant                   |                            X           X     X        X                  |          8 |
                                            __________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hemangioma                           |                                              X                           |          1 |
      Histiocytic Sarcoma                  |                                                                          |          1 |
      Lymphoma Malignant                   |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Harderian Gland                         |                +              +                                          |   2        |
      Adenoma                              |                               X                                          |          1 |
      Carcinoma                            |                X                                                         |          1 |
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Lymphoma Malignant                   |                         X                             X                  |          5 |
                                            __________________________________________________________________________|____________|
   Ureter                                  |                                                                          |   1        |
      Transitional Epithelium, Papilloma   |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Histiocytic Sarcoma                  |                                                                          |          1 |
      Leiomyosarcoma, Metastatic, Uterus   |                                                                      X   |          1 |
      Lymphoma Malignant                   |                                        X                                 |          3 |
 __________________________________________________________________________________________________________________________________ 
 SYSTEMIC LESIONS                          |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Histiocytic Sarcoma                  |                                                                          |          3 |
      Lymphoma Malignant                   |                   X     X  X           X     X        X                  |         12 |
 __________________________________________________________________________________________________________________________________ 

                         * : 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  25                                                               
NTP Experiment-Test: 60968-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 03/17/97  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 18:22:07  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 6| 7| 7| 6| 7| 7| 7| 6| 7| 7| 7| 6| 7| 7| 6| 7| 7| 7| 7| 6| 7| 7| 7| 7|             
                             DAY ON TEST   | 0| 8| 3| 3| 5| 3| 3| 3| 6| 3| 3| 3| 5| 3| 3| 5| 3| 3| 3| 3| 5| 3| 3| 3| 3|             
                                           | 2| 1| 7| 6| 2| 7| 5| 5| 5| 6| 7| 6| 3| 7| 6| 3| 7| 5| 7| 7| 3| 6| 6| 6| 7|             
 _____________________________________________________________________________________________________________________|             
                                           | 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|             
    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  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |       X                                                                  |             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |       X                 X                                                |             
                                            __________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hepatocellular Carcinoma             |                X                                                         |             
      Hepatocellular Adenoma               |             X                             X        X  X           X  X   |             
      Hepatocellular Adenoma, Multiple     |                                                                          |             
      Lymphoma Malignant                   | X                       X     X                                          |             
                                            __________________________________________________________________________|             
   Mesentery                               |                                                                          |             
                                            __________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                         X     X                                          |             
                                            __________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                         X     X                                          |             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                         X                                                |             
      Squamous Cell Papilloma              |                                                                          |             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                         X                                                |             
                                            __________________________________________________________________________|             
   Tooth                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hepatocellular Carcinoma, Metastatic,|                                                                          |             
           Liver                           |                X                                                         |             
                                            __________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Pheochromocytoma Malignant           |                                                                          |             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       | +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  M  M|             
                                            __________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +|             
      Pars Distalis, Adenoma               |       X                       X        X  X  X        X                  |             
      Pars Intermedia, Adenoma             |                                                             X            |             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             

                                                             Page  26                                                               
NTP Experiment-Test: 60968-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 03/17/97  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 18:22:07  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 6| 7| 7| 6| 7| 7| 7| 6| 7| 7| 7| 6| 7| 7| 6| 7| 7| 7| 7| 6| 7| 7| 7| 7|             
                             DAY ON TEST   | 0| 8| 3| 3| 5| 3| 3| 3| 6| 3| 3| 3| 5| 3| 3| 5| 3| 3| 3| 3| 5| 3| 3| 3| 3|             
                                           | 2| 1| 7| 6| 2| 7| 5| 5| 5| 6| 7| 6| 3| 7| 6| 3| 7| 5| 7| 7| 3| 6| 6| 6| 7|             
 _____________________________________________________________________________________________________________________|             
                                           | 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|             
    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                   |                                                                          |             
                                           |                                                                          |             
      Follicular Cell, Adenoma             |          X                                                               |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Clitoral Gland                          | +  +  +  +  +  +  M  +  +  +  M  +  +  +  +  +  +  M  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Ovary                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cystadenoma                          |                                                                          |             
      Hemangiosarcoma                      | X                                                                        |             
      Luteoma                              |                                                                          |             
      Lymphoma Malignant                   |                         X                                                |             
                                            __________________________________________________________________________|             
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                         X     X                                          |             
      Polyp Stromal                        |                   X                       X                          X   |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                         X     X                                          |             
                                            __________________________________________________________________________|             
   Lymph Node                              |                               +        +                                 |             
      Renal, Lymphoma Malignant            |                               X        X                                 |             
                                            __________________________________________________________________________|             
   Lymph Node, Bronchial                   | +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  M|             
      Lymphoma Malignant                   |                         X     X                 X                        |             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  M  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                         X     X                                          |             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  M  +  +  +  +  +  +  +  +  +  +  +  I  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |       X                 X     X                 X                        |             
                                            __________________________________________________________________________|             
   Lymph Node, Mediastinal                 | +  +  +  M  +  +  M  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  M  +  +|             
      Lymphoma Malignant                   |                         X     X                 X                        |             
                                            __________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   | X     X                 X     X  X     X        X  X                     |             
                                            __________________________________________________________________________|             
   Thymus                                  | +  +  M  +  M  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  M  +  +  +  +|             
      Lymphoma Malignant                   |                         X                                                |             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Squamous Cell Carcinoma              |                                                                          |             
      Subcutaneous Tissue, Fibrosarcoma    |    X                                                                     |             
      Subcutaneous Tissue, Histiocytic     |                                                                          |             
          Sarcoma                          |                X                                                         |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             

                                                             Page  27                                                               
NTP Experiment-Test: 60968-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 03/17/97  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 18:22:07  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 6| 7| 7| 6| 7| 7| 7| 6| 7| 7| 7| 6| 7| 7| 6| 7| 7| 7| 7| 6| 7| 7| 7| 7|             
                             DAY ON TEST   | 0| 8| 3| 3| 5| 3| 3| 3| 6| 3| 3| 3| 5| 3| 3| 5| 3| 3| 3| 3| 5| 3| 3| 3| 3|             
                                           | 2| 1| 7| 6| 2| 7| 5| 5| 5| 6| 7| 6| 3| 7| 6| 3| 7| 5| 7| 7| 3| 6| 6| 6| 7|             
 _____________________________________________________________________________________________________________________|             
                                           | 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|             
    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|             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM - cont             |                                                                          |             
                                           |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Larynx                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Alveolar/Bronchiolar Adenoma         |                      X     X                                             |             
      Alveolar/Bronchiolar Carcinoma       |                                                                          |             
      Hepatocellular Carcinoma, Metastatic,|                                                                          |             
           Liver                           |                X                                                         |             
      Lymphoma Malignant                   |                         X     X                 X                        |             
      Squamous Cell Carcinoma, Metastatic, |                                                                          |             
           Skin                            |                                                                          |             
                                            __________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Eye                                     |                      +                                                   |             
                                            __________________________________________________________________________|             
   Harderian Gland                         |                                                                         +|             
      Adenoma                              |                                                                         X|             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                         X     X                                          |             
                                            __________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |       X                 X     X                                          |             
 _____________________________________________________________________________________________________________________|             
 SYSTEMIC LESIONS                          |                                                                          |             
                                            __________________________________________________________________________|             
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Histiocytic Sarcoma                  |                X                                                         |             
      Lymphoma Malignant                   | X     X                 X     X  X     X        X  X                     |             
 _____________________________________________________________________________________________________________________|             

                                                             Page  28                                                               
NTP Experiment-Test: 60968-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 03/17/97  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 18:22:07  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 4| 7| 6| 6| 7| 4| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 4| 7| 7| 7| 7| 6|            |
                             DAY ON TEST   | 3| 3| 3| 1| 3| 8| 1| 3| 1| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 8| 3| 3| 3| 3| 5|            |
                                           | 5| 5| 7| 5| 6| 2| 1| 6| 5| 5| 6| 6| 7| 6| 6| 6| 7| 6| 7| 3| 6| 6| 5| 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 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      |
    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  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +|  47        |
      Lymphoma Malignant                   |                                                             X            |          1 |
                                            __________________________________________________________________________|____________|
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  I  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
      Lymphoma Malignant                   |                                                                      X   |          1 |
                                            __________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Lymphoma Malignant                   |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Lymphoma Malignant                   |                                     X                                    |          3 |
                                            __________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hepatocellular Carcinoma             |                X           X                                             |          3 |
      Hepatocellular Adenoma               |                   X                                            X         |          8 |
      Hepatocellular Adenoma, Multiple     |                                                                      X   |          1 |
      Lymphoma Malignant                   |                                                 X           X           X|          6 |
                                            __________________________________________________________________________|____________|
   Mesentery                               | +           +                                            +               |   3        |
                                            __________________________________________________________________________|____________|
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Lymphoma Malignant                   |                                                             X            |          3 |
                                            __________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Lymphoma Malignant                   |                                                                          |          2 |
                                            __________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Lymphoma Malignant                   |                                                                          |          1 |
      Squamous Cell Papilloma              |                               X                                          |          1 |
                                            __________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Lymphoma Malignant                   |                                                             X            |          2 |
                                            __________________________________________________________________________|____________|
   Tooth                                   |                         +                                                |   1        |
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hepatocellular Carcinoma, Metastatic,|                                                                          |            |
           Liver                           |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Pheochromocytoma Malignant           |                   X                                                      |          1 |
                                            __________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  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  29                                                               
NTP Experiment-Test: 60968-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 03/17/97  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 18:22:07  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 4| 7| 6| 6| 7| 4| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 4| 7| 7| 7| 7| 6|            |
                             DAY ON TEST   | 3| 3| 3| 1| 3| 8| 1| 3| 1| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 8| 3| 3| 3| 3| 5|            |
                                           | 5| 5| 7| 5| 6| 2| 1| 6| 5| 5| 6| 6| 7| 6| 6| 6| 7| 6| 7| 3| 6| 6| 5| 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 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      |
    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  +  +  +  +  +  +  +  +  +|  40        |
                                            __________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Pars Distalis, Adenoma               | X                          X                                         X   |          9 |
      Pars Intermedia, Adenoma             |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Follicular Cell, Adenoma             |                                                                          |          1 |
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
                                           |                                                                          |            |
    None                                   |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Clitoral Gland                          | +  M  +  +  M  M  +  +  +  +  +  M  +  I  +  +  +  +  +  M  +  +  M  +  +|  40        |
                                            __________________________________________________________________________|____________|
   Ovary                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Cystadenoma                          |                                                                X        X|          2 |
      Hemangiosarcoma                      |                                                                          |          1 |
      Luteoma                              |                      X                                                   |          1 |
      Lymphoma Malignant                   |                                                 X                        |          2 |
                                            __________________________________________________________________________|____________|
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Lymphoma Malignant                   |                                                       X                  |          3 |
      Polyp Stromal                        |                            X                                      X      |          5 |
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Lymphoma Malignant                   |                                                    X                     |          3 |
                                            __________________________________________________________________________|____________|
   Lymph Node                              | +                                                           +            |   4        |
      Renal, Lymphoma Malignant            |                                                             X            |          3 |
                                            __________________________________________________________________________|____________|
   Lymph Node, Bronchial                   | +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  M  +  +  +  +  +  +  +  M|  44        |
      Lymphoma Malignant                   |                                                       X     X        X   |          6 |
                                            __________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  M  +  M  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +|  45        |
      Lymphoma Malignant                   |                                                                          |          2 |
                                            __________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +|  47        |
      Lymphoma Malignant                   |                                           X                 X            |          6 |
                                            __________________________________________________________________________|____________|
   Lymph Node, Mediastinal                 | M  +  +  +  M  +  +  M  +  +  M  +  +  M  +  +  M  +  +  M  +  +  M  +  +|  38        |
      Lymphoma Malignant                   |                                           X           X     X        X   |          7 |
                                            __________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Lymphoma Malignant                   | X  X        X                             X     X  X  X     X           X|         17 |
                                            __________________________________________________________________________|____________|
   Thymus                                  | +  M  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +|  43        |
      Lymphoma Malignant                   |                                                                          |          1 |
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY 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  30                                                               
NTP Experiment-Test: 60968-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 03/17/97  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 18:22:07  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 4| 7| 6| 6| 7| 4| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 4| 7| 7| 7| 7| 6|            |
                             DAY ON TEST   | 3| 3| 3| 1| 3| 8| 1| 3| 1| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 8| 3| 3| 3| 3| 5|            |
                                           | 5| 5| 7| 5| 6| 2| 1| 6| 5| 5| 6| 6| 7| 6| 6| 6| 7| 6| 7| 3| 6| 6| 5| 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 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      |
    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               |                                                                          |            |
                                           |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Squamous Cell Carcinoma              |                                                                         X|          1 |
      Subcutaneous Tissue, Fibrosarcoma    |                   X                                                      |          2 |
      Subcutaneous Tissue, Histiocytic     |                                                                          |            |
          Sarcoma                          |                                                                          |          1 |
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Larynx                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Alveolar/Bronchiolar Adenoma         | X                                                                        |          3 |
      Alveolar/Bronchiolar Carcinoma       |                                                 X                        |          1 |
      Hepatocellular Carcinoma, Metastatic,|                                                                          |            |
           Liver                           |                                                                          |          1 |
      Lymphoma Malignant                   |                                                             X            |          4 |
      Squamous Cell Carcinoma, Metastatic, |                                                                          |            |
           Skin                            |                                                                         X|          1 |
                                            __________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Eye                                     |    +                                                           +         |   3        |
                                            __________________________________________________________________________|____________|
   Harderian Gland                         |                      +                                                   |   2        |
      Adenoma                              |                                                                          |          1 |
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Lymphoma Malignant                   |                                                 X                        |          3 |
                                            __________________________________________________________________________|____________|
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Lymphoma Malignant                   |                                                       X     X            |          5 |
 __________________________________________________________________________________________________________________________________ 
 SYSTEMIC LESIONS                          |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  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  31                                                               
NTP Experiment-Test: 60968-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 03/17/97  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 18:22:07  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 4| 7| 6| 6| 7| 4| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 4| 7| 7| 7| 7| 6|            |
                             DAY ON TEST   | 3| 3| 3| 1| 3| 8| 1| 3| 1| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 8| 3| 3| 3| 3| 5|            |
                                           | 5| 5| 7| 5| 6| 2| 1| 6| 5| 5| 6| 6| 7| 6| 6| 6| 7| 6| 7| 3| 6| 6| 5| 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 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      |
    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|            |
 __________________________________________________________________________________________________________________________________ 
 SYSTEMIC LESIONS - cont                   |                                                                          |            |
                                           |                                                                          |            |
      Histiocytic Sarcoma                  |                                                                          |          1 |
      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  32                                                               
NTP Experiment-Test: 60968-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 03/17/97  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 18:22:07  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 6| 7| 7| 7|             
                             DAY ON TEST   | 3| 3| 3| 3| 3| 3| 8| 3| 3| 3| 3| 3| 3| 3| 3| 6| 3| 3| 3| 3| 3| 5| 3| 3| 3|             
                                           | 4| 5| 3| 4| 4| 3| 5| 3| 3| 4| 3| 3| 5| 5| 4| 4| 3| 3| 3| 4| 3| 9| 4| 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                             | +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +|             
      Sarcoma, Metastatic, Skin            |                   X                                                      |             
                                            __________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +|             
      Leiomyoma                            |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  A  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +|             
                                            __________________________________________________________________________|             
   Liver                                   | +     +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cholangioma                          |                      X                                                   |             
      Hemangiosarcoma                      |                                                                      X   |             
      Hepatocellular Carcinoma             | X                          X        X  X     X                 X  X      |             
      Hepatocellular Carcinoma, Multiple   |                X                                                         |             
      Hepatocellular Adenoma               | X                       X              X              X                  |             
      Hepatocellular Adenoma, Multiple     |          X                       X              X                        |             
                                            __________________________________________________________________________|             
   Mesentery                               |                                                                          |             
                                            __________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Squamous Cell Papilloma              |                      X                                                   |             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Adenoma                              |                                                    X                     |             
      Capsule, Adenoma                     |                                                             X            |             
                                            __________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Adenoma                              |                                                                          |             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       | +  +  +  +  M  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Follicular Cell, Adenoma             |    X                 X                                                   |             
      Follicular Cell, Carcinoma           |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |                                                                          |             
 _____________________________________________________________________________________________________________________|             

                                                             Page  33                                                               
NTP Experiment-Test: 60968-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 03/17/97  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 18:22:07  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 6| 7| 7| 7|             
                             DAY ON TEST   | 3| 3| 3| 3| 3| 3| 8| 3| 3| 3| 3| 3| 3| 3| 3| 6| 3| 3| 3| 3| 3| 5| 3| 3| 3|             
                                           | 4| 5| 3| 4| 4| 3| 5| 3| 3| 4| 3| 3| 5| 5| 4| 4| 3| 3| 3| 4| 3| 9| 4| 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                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Preputial Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Prostate                                | +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Carcinoma                            |                                                                      X   |             
                                            __________________________________________________________________________|             
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemangiosarcoma                      |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node, Bronchial                   | +  +  M  +  +  +  M  +  +  +  +  +  M  M  +  +  +  M  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  M  +  +  M  M  +  +  +  +  M  +  M  +  M  +  +  +  +  +  +  +  +  M|             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node, Mediastinal                 | M  +  +  +  +  M  M  M  +  M  M  +  M  +  M  +  M  +  M  M  M  M  M  M  +|             
      Fibrosarcoma, Metastatic, Skin       |                                                                          |             
                                            __________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemangiosarcoma                      |                                                                      X   |             
                                            __________________________________________________________________________|             
   Thymus                                  | 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  M|             
                                            __________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Subcutaneous Tissue, Fibrosarcoma    |                                                                          |             
      Subcutaneous Tissue, Sarcoma         |                   X                                                      |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Larynx                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Alveolar/Bronchiolar Adenoma         |                                                    X              X      |             
      Alveolar/Bronchiolar Carcinoma       |             X                                   X     X        X         |             
      Alveolar/Bronchiolar Carcinoma,      |                                                                          |             
          Multiple                         |                                                                          |             
      Carcinoma, Metastatic, Thyroid Gland |                                                                          |             
      Sarcoma, Metastatic, Skin            |                   X                                                      |             
      Mediastinum, Alveolar/Bronchiolar    |                                                                          |             
          Carcinoma, Metastatic, Lung      |                                                                          |             
      Mediastinum, Fibrosarcoma,           |                                                                          |             
 _____________________________________________________________________________________________________________________|             

                                                             Page  34                                                               
NTP Experiment-Test: 60968-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 03/17/97  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 18:22:07  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 6| 7| 7| 7|             
                             DAY ON TEST   | 3| 3| 3| 3| 3| 3| 8| 3| 3| 3| 3| 3| 3| 3| 3| 6| 3| 3| 3| 3| 3| 5| 3| 3| 3|             
                                           | 4| 5| 3| 4| 4| 3| 5| 3| 3| 4| 3| 3| 5| 5| 4| 4| 3| 3| 3| 4| 3| 9| 4| 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|             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM - cont                 |                                                                          |             
                                           |                                                                          |             
          Metastatic, Skin                 |                                                                          |             
                                            __________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Vomeronasal Organ, Adenoma           |       X                                                                  |             
                                            __________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Harderian Gland                         |                                                    +                     |             
      Adenoma                              |                                                    X                     |             
      Carcinoma                            |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SYSTEMIC LESIONS                          |                                                                          |             
                                            __________________________________________________________________________|             
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             

                                                             Page  35                                                               
NTP Experiment-Test: 60968-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 03/17/97  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 18:22:07  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 6| 6| 7| 7| 7| 7| 7| 4| 7| 7| 7| 7| 7| 5| 7| 7| 6| 7| 7| 6| 7| 7| 6| 7|            |
                             DAY ON TEST   | 3| 3| 3| 3| 3| 3| 3| 3| 5| 3| 3| 3| 3| 3| 2| 3| 3| 7| 3| 3| 3| 3| 3| 8| 3|            |
                                           | 4| 9| 9| 3| 3| 3| 4| 4| 5| 3| 4| 4| 3| 4| 0| 3| 4| 6| 3| 3| 9| 5| 4| 2| 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   | 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                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +|  47        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Sarcoma, Metastatic, Skin            |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Leiomyoma                            |                                                          X               |          1 |
                                            __________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
                                            __________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                            __________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                            __________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Cholangioma                          |                                                                          |          1 |
      Hemangiosarcoma                      |                                                                          |          1 |
      Hepatocellular Carcinoma             |                X                 X  X              X     X  X        X   |         14 |
      Hepatocellular Carcinoma, Multiple   |       X                                X                                 |          3 |
      Hepatocellular Adenoma               |    X                       X                                      X     X|          8 |
      Hepatocellular Adenoma, Multiple     |                      X                                                   |          4 |
                                            __________________________________________________________________________|____________|
   Mesentery                               |                                                       +                  |   1        |
                                            __________________________________________________________________________|____________|
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Squamous Cell Papilloma              |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Adenoma                              |                                                                          |          1 |
      Capsule, Adenoma                     |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Adenoma                              |                      X                                                   |          1 |
                                            __________________________________________________________________________|____________|
   Parathyroid Gland                       | +  +  M  M  +  +  +  +  +  +  +  +  M  I  +  M  +  +  +  +  +  +  +  +  +|  43        |
                                            __________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +|  49        |
                                            __________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Follicular Cell, Adenoma             |       X                                                                  |          3 |
      Follicular Cell, Carcinoma           |    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  36                                                               
NTP Experiment-Test: 60968-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 03/17/97  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 18:22:07  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 6| 6| 7| 7| 7| 7| 7| 4| 7| 7| 7| 7| 7| 5| 7| 7| 6| 7| 7| 6| 7| 7| 6| 7|            |
                             DAY ON TEST   | 3| 3| 3| 3| 3| 3| 3| 3| 5| 3| 3| 3| 3| 3| 2| 3| 3| 7| 3| 3| 3| 3| 3| 8| 3|            |
                                           | 4| 9| 9| 3| 3| 3| 4| 4| 5| 3| 4| 4| 3| 4| 0| 3| 4| 6| 3| 3| 9| 5| 4| 2| 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   | 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|            |
 __________________________________________________________________________________________________________________________________ 
 GENERAL BODY SYSTEM                       |                                                                          |            |
                                           |                                                                          |            |
    None                                   |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Preputial Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Prostate                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                            __________________________________________________________________________|____________|
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Carcinoma                            |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hemangiosarcoma                      |                                                       X                  |          1 |
                                            __________________________________________________________________________|____________|
   Lymph Node, Bronchial                   | +  M  +  +  M  +  +  +  M  M  +  +  M  +  M  M  +  +  +  +  +  +  +  M  +|  37        |
                                            __________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | M  M  +  M  M  +  M  +  M  +  +  +  M  M  +  M  M  M  M  +  +  M  M  M  M|  27        |
                                            __________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Lymphoma Malignant                   |                                                             X            |          1 |
                                            __________________________________________________________________________|____________|
   Lymph Node, Mediastinal                 | +  M  +  M  +  +  +  +  +  +  +  +  +  +  +  M  M  M  +  +  M  +  +  +  +|  29        |
      Fibrosarcoma, Metastatic, Skin       |                                           X                              |          1 |
                                            __________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hemangiosarcoma                      |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Thymus                                  | +  +  M  +  +  +  +  +  M  +  +  +  M  M  M  +  +  +  M  +  M  +  M  +  +|  39        |
 _____________________________________________________________________________________________________________________|            |
 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                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +|  49        |
      Subcutaneous Tissue, Fibrosarcoma    |                                           X                              |          1 |
      Subcutaneous Tissue, Sarcoma         |                                                                          |          1 |
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Larynx                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Alveolar/Bronchiolar Adenoma         |                                        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  37                                                               
NTP Experiment-Test: 60968-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 03/17/97  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 18:22:07  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 6| 6| 7| 7| 7| 7| 7| 4| 7| 7| 7| 7| 7| 5| 7| 7| 6| 7| 7| 6| 7| 7| 6| 7|            |
                             DAY ON TEST   | 3| 3| 3| 3| 3| 3| 3| 3| 5| 3| 3| 3| 3| 3| 2| 3| 3| 7| 3| 3| 3| 3| 3| 8| 3|            |
                                           | 4| 9| 9| 3| 3| 3| 4| 4| 5| 3| 4| 4| 3| 4| 0| 3| 4| 6| 3| 3| 9| 5| 4| 2| 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   | 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                 |                                                                          |            |
                                           |                                                                          |            |
      Alveolar/Bronchiolar Carcinoma       |             X           X                                                |          6 |
      Alveolar/Bronchiolar Carcinoma,      |                                                                          |            |
          Multiple                         |                                                             X            |          1 |
      Carcinoma, Metastatic, Thyroid Gland |    X                                                                     |          1 |
      Sarcoma, Metastatic, Skin            |                                                                          |          1 |
      Mediastinum, Alveolar/Bronchiolar    |                                                                          |            |
          Carcinoma, Metastatic, Lung      |                         X                                                |          1 |
      Mediastinum, Fibrosarcoma,           |                                                                          |            |
          Metastatic, Skin                 |                                           X                              |          1 |
                                            __________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Vomeronasal Organ, Adenoma           |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Harderian Gland                         |                               +     +                                    |   3        |
      Adenoma                              |                                                                          |          1 |
      Carcinoma                            |                               X     X                                    |          2 |
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 __________________________________________________________________________________________________________________________________ 
 SYSTEMIC LESIONS                          |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      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  38                                                               
NTP Experiment-Test: 60968-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 03/17/97  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 18:22:07  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 5| 6| 7| 6| 4| 6| 7| 7| 7| 7| 7| 7| 7| 7| 5| 7| 7| 7| 7| 7| 7| 7| 7| 7|             
                             DAY ON TEST   | 0| 8| 7| 3| 8| 1| 2| 3| 3| 3| 3| 3| 3| 3| 3| 7| 3| 3| 3| 3| 3| 3| 3| 3| 3|             
                                           | 9| 0| 0| 4| 0| 5| 3| 5| 4| 4| 4| 4| 5| 4| 5| 3| 3| 3| 4| 5| 4| 3| 4| 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   | 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  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               | +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hepatocholangiocarcinoma, Metastatic,|                                                                          |             
           Liver                           |                                              X                           |             
      Lymphoma Malignant                   |                               X                                          |             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hepatocellular Carcinoma             | X  X        X                 X                       X              X   |             
      Hepatocellular Carcinoma, Multiple   |                   X                                                      |             
      Hepatocellular Adenoma               |       X           X                       X        X  X     X     X      |             
      Hepatocellular Adenoma, Multiple     |                                     X                                    |             
      Hepatocholangiocarcinoma             |                                              X                           |             
                                            __________________________________________________________________________|             
   Mesentery                               |                +     +                          +                        |             
                                            __________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hepatocholangiocarcinoma, Metastatic,|                                                                          |             
           Liver                           |                                              X                           |             
                                            __________________________________________________________________________|             
   Tooth                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Adenoma                              |                                                                         X|             
                                            __________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Pheochromocytoma Benign              |                                                                          |             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       | +  M  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  M  +  +  M  +  M  +|             
                                            __________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Follicular Cell, Adenoma             |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |                                                                          |             
 _____________________________________________________________________________________________________________________|             

                                                             Page  39                                                               
NTP Experiment-Test: 60968-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 03/17/97  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 18:22:07  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 5| 6| 7| 6| 4| 6| 7| 7| 7| 7| 7| 7| 7| 7| 5| 7| 7| 7| 7| 7| 7| 7| 7| 7|             
                             DAY ON TEST   | 0| 8| 7| 3| 8| 1| 2| 3| 3| 3| 3| 3| 3| 3| 3| 7| 3| 3| 3| 3| 3| 3| 3| 3| 3|             
                                           | 9| 0| 0| 4| 0| 5| 3| 5| 4| 4| 4| 4| 5| 4| 5| 3| 3| 3| 4| 5| 4| 3| 4| 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   | 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                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Preputial Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Prostate                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Lymph Node, Bronchial                   | +  +  M  +  M  +  M  M  +  +  M  +  +  +  M  +  +  M  +  +  M  +  +  +  M|             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  | M  M  +  +  M  +  +  M  +  M  +  M  +  +  M  M  +  +  M  M  M  +  M  M  M|             
      Lymphoma Malignant                   |                                                    X                     |             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                               X        X           X                     |             
                                            __________________________________________________________________________|             
   Lymph Node, Mediastinal                 | +  +  +  M  M  M  +  +  +  +  +  M  M  +  M  M  M  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemangiosarcoma                      |                         X                                               X|             
      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|             
                                            __________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Squamous Cell Carcinoma              |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Larynx                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Alveolar/Bronchiolar Adenoma         |                                                                          |             
      Alveolar/Bronchiolar Adenoma,        |                                                                          |             
          Multiple                         |                                                                          |             
      Alveolar/Bronchiolar Carcinoma       |                                                                          |             
      Hepatocellular Carcinoma, Metastatic,|                                                                          |             
           Liver                           |             X     X                                                      |             
      Hepatocholangiocarcinoma, Metastatic,|                                                                          |             
           Liver                           |                                              X                           |             
      Mediastinum,                         |                                                                          |             
          Hepatocholangiocarcinoma,        |                                                                          |             
 _____________________________________________________________________________________________________________________|             

                                                             Page  40                                                               
NTP Experiment-Test: 60968-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 03/17/97  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 18:22:07  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 5| 6| 7| 6| 4| 6| 7| 7| 7| 7| 7| 7| 7| 7| 5| 7| 7| 7| 7| 7| 7| 7| 7| 7|             
                             DAY ON TEST   | 0| 8| 7| 3| 8| 1| 2| 3| 3| 3| 3| 3| 3| 3| 3| 7| 3| 3| 3| 3| 3| 3| 3| 3| 3|             
                                           | 9| 0| 0| 4| 0| 5| 3| 5| 4| 4| 4| 4| 5| 4| 5| 3| 3| 3| 4| 5| 4| 3| 4| 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   | 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|             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM - cont                 |                                                                          |             
                                           |                                                                          |             
          Metastatic, Liver                |                                              X                           |             
                                            __________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Harderian Gland                         |    +                                                                 +   |             
      Carcinoma                            |    X                                                                 X   |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hepatocholangiocarcinoma, Metastatic,|                                                                          |             
           Liver                           |                                              X                           |             
                                            __________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SYSTEMIC LESIONS                          |                                                                          |             
                                            __________________________________________________________________________|             
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                               X        X           X              X      |             
 _____________________________________________________________________________________________________________________|             

                                                             Page  41                                                               
NTP Experiment-Test: 60968-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 03/17/97  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 18:22:07  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 6| 7| 6|            |
                             DAY ON TEST   | 3| 3| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 0| 3| 3| 3| 3| 1| 3| 3| 3| 3| 4| 3| 1|            |
                                           | 5| 4| 3| 4| 5| 2| 5| 4| 4| 3| 4| 4| 5| 5| 4| 3| 3| 2| 4| 4| 4| 4| 9| 4| 1|            |
 _____________________________________________________________________________________________________________________|     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  +  +  +  +  +  +  +  M  +  +  M  +|  43        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
                                            __________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  A|  46        |
                                            __________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A|  49        |
      Hepatocholangiocarcinoma, Metastatic,|                                                                          |            |
           Liver                           |                                                                          |          1 |
      Lymphoma Malignant                   |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                            __________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hepatocellular Carcinoma             |    X  X        X        X                          X              X      |         12 |
      Hepatocellular Carcinoma, Multiple   |                                                                         X|          2 |
      Hepatocellular Adenoma               | X        X                 X        X                       X     X      |         13 |
      Hepatocellular Adenoma, Multiple     |                                                                          |          1 |
      Hepatocholangiocarcinoma             |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Mesentery                               |                                                                          |   3        |
                                            __________________________________________________________________________|____________|
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                            __________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hepatocholangiocarcinoma, Metastatic,|                                                                          |            |
           Liver                           |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Tooth                                   |             +              +  +                                          |   3        |
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Adenoma                              |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Pheochromocytoma Benign              |                         X                                                |          1 |
                                            __________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                            __________________________________________________________________________|____________|
   Parathyroid Gland                       | +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  M  M  +  +  M  +  +  +  +|  41        |
                                            __________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  M  M  +  +  +  +  +  +  +  +|  47        |
                                            __________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Follicular Cell, Adenoma             | 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  42                                                               
NTP Experiment-Test: 60968-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 03/17/97  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 18:22:07  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 6| 7| 6|            |
                             DAY ON TEST   | 3| 3| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 0| 3| 3| 3| 3| 1| 3| 3| 3| 3| 4| 3| 1|            |
                                           | 5| 4| 3| 4| 5| 2| 5| 4| 4| 3| 4| 4| 5| 5| 4| 3| 3| 2| 4| 4| 4| 4| 9| 4| 1|            |
 _____________________________________________________________________________________________________________________|     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|            |
 __________________________________________________________________________________________________________________________________ 
 GENERAL BODY SYSTEM                       |                                                                          |            |
                                           |                                                                          |            |
    None                                   |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Preputial Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Prostate                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Lymph Node, Bronchial                   | +  +  M  +  M  M  +  +  +  M  M  +  +  M  M  +  +  +  +  +  +  +  +  +  +|  34        |
                                            __________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | +  M  M  M  +  M  +  +  +  M  +  M  M  M  +  +  M  +  +  +  +  +  M  +  M|  25        |
      Lymphoma Malignant                   |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
      Lymphoma Malignant                   |                                                                          |          3 |
                                            __________________________________________________________________________|____________|
   Lymph Node, Mediastinal                 | +  M  +  +  +  +  +  M  +  M  +  +  +  M  +  +  +  M  +  +  +  M  M  +  M|  34        |
                                            __________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hemangiosarcoma                      |                                                                          |          2 |
      Lymphoma Malignant                   |                                                                          |          2 |
                                            __________________________________________________________________________|____________|
   Thymus                                  | +  +  M  +  +  +  M  +  +  +  M  +  M  +  +  +  +  M  +  +  +  +  +  +  +|  39        |
      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                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Squamous Cell Carcinoma              |                                                 X                        |          1 |
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Larynx                                  | +  +  +  +  +  +  +  I  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                            __________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Alveolar/Bronchiolar Adenoma         |             X                                      X                     |          2 |
      Alveolar/Bronchiolar Adenoma,        |                                                                          |            |
 __________________________________________________________________________________________________________________________________ 

                         * : 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: 60968-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 03/17/97  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 18:22:07  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 6| 7| 6|            |
                             DAY ON TEST   | 3| 3| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 0| 3| 3| 3| 3| 1| 3| 3| 3| 3| 4| 3| 1|            |
                                           | 5| 4| 3| 4| 5| 2| 5| 4| 4| 3| 4| 4| 5| 5| 4| 3| 3| 2| 4| 4| 4| 4| 9| 4| 1|            |
 _____________________________________________________________________________________________________________________|     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                         |                                                       X                  |          1 |
      Alveolar/Bronchiolar Carcinoma       |             X              X  X  X     X                 X               |          6 |
      Hepatocellular Carcinoma, Metastatic,|                                                                          |            |
           Liver                           |       X                 X                                                |          4 |
      Hepatocholangiocarcinoma, Metastatic,|                                                                          |            |
           Liver                           |                                                                          |          1 |
      Mediastinum,                         |                                                                          |            |
          Hepatocholangiocarcinoma,        |                                                                          |            |
          Metastatic, Liver                |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Harderian Gland                         |                                                                          |   2        |
      Carcinoma                            |                                                                          |          2 |
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hepatocholangiocarcinoma, Metastatic,|                                                                          |            |
           Liver                           |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 __________________________________________________________________________________________________________________________________ 
 SYSTEMIC LESIONS                          |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      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  44                                                               
NTP Experiment-Test: 60968-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 03/17/97  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 18:22:07  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 6| 7| 4| 7| 7| 7| 7| 7| 7| 0| 7| 6| 7| 7| 7| 7| 6| 7| 7| 3| 7| 7| 7| 5| 7|             
                             DAY ON TEST   | 3| 3| 2| 3| 3| 3| 3| 3| 3| 4| 3| 4| 3| 3| 3| 3| 3| 3| 3| 5| 3| 3| 3| 2| 3|             
                                           | 2| 3| 1| 5| 4| 4| 4| 3| 3| 3| 3| 9| 3| 4| 4| 5| 0| 4| 3| 9| 4| 5| 5| 9| 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 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|             
    1000 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  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  A  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  A  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  A  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  A  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hepatocellular Carcinoma             |       X                          X        X                          X  X|             
      Hepatocellular Carcinoma, Multiple   |                                        X     X  X                        |             
      Hepatocellular Adenoma               |                X     X  X                 X           X     X            |             
      Hepatocellular Adenoma, Multiple     |                                                                          |             
                                            __________________________________________________________________________|             
   Mesentery                               |    +                                            +        +  +            |             
      Artery, Fibrous Histiocytoma         |                                                                          |             
                                            __________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Artery, Fibrous Histiocytoma         |                                                                          |             
                                            __________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Squamous Cell Papilloma              |                                                                          |             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      | +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Artery, Fibrous Histiocytoma         |                                                                          |             
                                            __________________________________________________________________________|             
   Tooth                                   |                      +                                   +               |             
      Odontoma                             |                                                          X               |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Capsule, Adenoma                     |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Adenoma                              |                X                                                         |             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       | +  +  +  +  +  +  M  +  +  M  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      C-Cell, Carcinoma                    |                                                                          |             
      Follicular Cell, Adenoma             |                                                                          |             
      Follicular Cell, Carcinoma           |                                  X                                       |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
 _____________________________________________________________________________________________________________________|             

                                                             Page  45                                                               
NTP Experiment-Test: 60968-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 03/17/97  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 18:22:07  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 6| 7| 4| 7| 7| 7| 7| 7| 7| 0| 7| 6| 7| 7| 7| 7| 6| 7| 7| 3| 7| 7| 7| 5| 7|             
                             DAY ON TEST   | 3| 3| 2| 3| 3| 3| 3| 3| 3| 4| 3| 4| 3| 3| 3| 3| 3| 3| 3| 5| 3| 3| 3| 2| 3|             
                                           | 2| 3| 1| 5| 4| 4| 4| 3| 3| 3| 3| 9| 3| 4| 4| 5| 0| 4| 3| 9| 4| 5| 5| 9| 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 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|             
    1000 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                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Penis                                   |                                                 +                        |             
                                            __________________________________________________________________________|             
   Preputial Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  I  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Prostate                                | +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +|             
                                            __________________________________________________________________________|             
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemangiosarcoma                      |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node, Bronchial                   | +  M  M  +  +  +  +  +  +  +  M  +  M  +  +  M  +  +  M  M  M  +  M  M  +|             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  M  +  +  +  +  M  M  +  +  +  M  +  +  M  +  +  M  +  M  +  M  +  +  M|             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  M  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                                              X                           |             
                                            __________________________________________________________________________|             
   Lymph Node, Mediastinal                 | +  M  M  +  +  M  M  M  +  M  +  +  M  M  +  +  M  M  +  +  +  +  M  M  +|             
      Alveolar/Bronchiolar Carcinoma,      |                                                                          |             
          Metastatic, Lung                 |                                                                          |             
                                            __________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemangiosarcoma                      |                                                                          |             
      Lymphoma Malignant                   |                                              X                           |             
                                            __________________________________________________________________________|             
   Thymus                                  | +  +  +  +  +  +  +  M  +  +  +  +  +  M  +  +  +  +  M  +  +  +  +  +  +|             
      Fibrous Histiocytoma                 |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 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                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Fibrous Histiocytoma                 |                                                                          |             
      Mast Cell Tumor Benign               |                                                                          |             
      Squamous Cell Papilloma              |                                                                          |             
      Subcutaneous Tissue, Sarcoma         |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hemangiosarcoma                      |                                                                          |             
                                            __________________________________________________________________________|             
   Skeletal Muscle                         |                                                                          |             
      Hemangiosarcoma                      |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Spinal Cord                             |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Larynx                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             

                                                             Page  46                                                               
NTP Experiment-Test: 60968-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 03/17/97  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 18:22:07  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 6| 7| 4| 7| 7| 7| 7| 7| 7| 0| 7| 6| 7| 7| 7| 7| 6| 7| 7| 3| 7| 7| 7| 5| 7|             
                             DAY ON TEST   | 3| 3| 2| 3| 3| 3| 3| 3| 3| 4| 3| 4| 3| 3| 3| 3| 3| 3| 3| 5| 3| 3| 3| 2| 3|             
                                           | 2| 3| 1| 5| 4| 4| 4| 3| 3| 3| 3| 9| 3| 4| 4| 5| 0| 4| 3| 9| 4| 5| 5| 9| 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 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|             
    1000 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              X                                         X  X         |             
      Alveolar/Bronchiolar Carcinoma       |                      X                                                   |             
      Alveolar/Bronchiolar Carcinoma,      |                                                                          |             
          Multiple                         |                                                                          |             
      Carcinoma, Metastatic, Harderian     |                                                                          |             
          Gland                            |                                     X                                    |             
      Carcinoma, Metastatic, Thyroid Gland |                                                                          |             
      Hepatocellular Carcinoma, Metastatic,|                                                                          |             
           Liver                           |                                              X  X                    X   |             
      Artery, Fibrous Histiocytoma         |                                                                          |             
      Artery, Mediastinum, Fibrous         |                                                                          |             
          Histiocytoma                     |                                                                          |             
      Mediastinum, Alveolar/Bronchiolar    |                                                                          |             
          Carcinoma, Metastatic, Lung      |                                                                          |             
                                            __________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Ear                                     |                                                             +            |             
                                            __________________________________________________________________________|             
   Eye                                     |                                     +                                    |             
                                            __________________________________________________________________________|             
   Harderian Gland                         |                                     +                                    |             
      Adenoma                              |                                                                          |             
      Carcinoma                            |                                     X                                    |             
      Sarcoma                              |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Artery, Fibrous Histiocytoma         |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 SYSTEMIC LESIONS                          |                                                                          |             
                                            __________________________________________________________________________|             
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                                              X                           |             
 _____________________________________________________________________________________________________________________|             

                                                             Page  47                                                               
NTP Experiment-Test: 60968-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 03/17/97  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 18:22:07  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 7| 4| 7| 4| 7| 5| 7| 7| 5| 3| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7|            |
                             DAY ON TEST   | 3| 3| 3| 3| 3| 3| 1| 3| 4| 3| 6| 3| 3| 3| 2| 3| 1| 3| 7| 3| 3| 3| 3| 2| 3|            |
                                           | 3| 4| 3| 3| 3| 3| 0| 3| 8| 4| 0| 3| 4| 5| 2| 3| 1| 3| 2| 3| 4| 3| 3| 8| 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   | 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      |
    1000 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  +  M  +  +  A  +  +  +  +  +  +|  42        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
                                            __________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  A  +  +  +  +  +  +|  47        |
                                            __________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
                                            __________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +|  47        |
                                            __________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hepatocellular Carcinoma             |                   X     X                                         X     X|          9 |
      Hepatocellular Carcinoma, Multiple   |                                                                          |          3 |
      Hepatocellular Adenoma               |    X                 X     X  X        X        X     X  X               |         14 |
      Hepatocellular Adenoma, Multiple     |             X                                                            |          1 |
                                            __________________________________________________________________________|____________|
   Mesentery                               |                                                                +         |   5        |
      Artery, Fibrous Histiocytoma         |                                                                X         |          1 |
                                            __________________________________________________________________________|____________|
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Artery, Fibrous Histiocytoma         |                                                                X         |          1 |
                                            __________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Squamous Cell Papilloma              |                                                       X                  |          1 |
                                            __________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Artery, Fibrous Histiocytoma         |                                                                X         |          1 |
                                            __________________________________________________________________________|____________|
   Tooth                                   |                                                                          |   2        |
      Odontoma                             |                                                                          |          1 |
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Capsule, Adenoma                     |                      X                                                   |          1 |
                                            __________________________________________________________________________|____________|
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Adenoma                              |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Parathyroid Gland                       | +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +|  45        |
                                            __________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                            __________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      C-Cell, Carcinoma                    |                X                                                         |          1 |
      Follicular Cell, 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  48                                                               
NTP Experiment-Test: 60968-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 03/17/97  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 18:22:07  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 7| 4| 7| 4| 7| 5| 7| 7| 5| 3| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7|            |
                             DAY ON TEST   | 3| 3| 3| 3| 3| 3| 1| 3| 4| 3| 6| 3| 3| 3| 2| 3| 1| 3| 7| 3| 3| 3| 3| 2| 3|            |
                                           | 3| 4| 3| 3| 3| 3| 0| 3| 8| 4| 0| 3| 4| 5| 2| 3| 1| 3| 2| 3| 4| 3| 3| 8| 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   | 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      |
    1000 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                   |                                                                          |            |
                                           |                                                                          |            |
      Follicular Cell, Carcinoma           |                                                                          |          1 |
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
                                           |                                                                          |            |
    None                                   |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Penis                                   |                                                                          |   1        |
                                            __________________________________________________________________________|____________|
   Preputial Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                            __________________________________________________________________________|____________|
   Prostate                                | +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  47        |
                                            __________________________________________________________________________|____________|
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hemangiosarcoma                      |                                                                      X   |          1 |
                                            __________________________________________________________________________|____________|
   Lymph Node, Bronchial                   | M  M  +  +  M  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  M  M  +  M|  33        |
                                            __________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | +  +  +  +  M  +  +  +  +  +  +  +  M  +  M  +  +  +  +  M  +  +  +  +  M|  36        |
                                            __________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  47        |
      Lymphoma Malignant                   |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Lymph Node, Mediastinal                 | +  +  +  M  +  M  M  +  +  M  M  M  M  +  M  +  +  M  +  +  +  M  +  +  +|  28        |
      Alveolar/Bronchiolar Carcinoma,      |                                                                          |            |
          Metastatic, Lung                 |                                        X                                 |          1 |
                                            __________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hemangiosarcoma                      |                                                                      X   |          1 |
      Lymphoma Malignant                   |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Thymus                                  | M  +  M  +  M  +  M  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +|  42        |
      Fibrous Histiocytoma                 |                                                                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                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Fibrous Histiocytoma                 | X                                                                        |          1 |
      Mast Cell Tumor Benign               |                      X                                                   |          1 |
      Squamous Cell Papilloma              |                                                       X                  |          1 |
      Subcutaneous Tissue, Sarcoma         |                                           X                              |          1 |
 _____________________________________________________________________________________________________________________|            |
 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  49                                                               
NTP Experiment-Test: 60968-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 03/17/97  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 18:22:07  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 7| 4| 7| 4| 7| 5| 7| 7| 5| 3| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7|            |
                             DAY ON TEST   | 3| 3| 3| 3| 3| 3| 1| 3| 4| 3| 6| 3| 3| 3| 2| 3| 1| 3| 7| 3| 3| 3| 3| 2| 3|            |
                                           | 3| 4| 3| 3| 3| 3| 0| 3| 8| 4| 0| 3| 4| 5| 2| 3| 1| 3| 2| 3| 4| 3| 3| 8| 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   | 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      |
    1000 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             |                                                                          |            |
                                           |                                                                          |            |
      Hemangiosarcoma                      |                                                                      X   |          1 |
                                            __________________________________________________________________________|____________|
   Skeletal Muscle                         |                                                                      +   |   1        |
      Hemangiosarcoma                      |                                                                      X   |          1 |
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Spinal Cord                             |                               +                                          |   1        |
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Larynx                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Alveolar/Bronchiolar Adenoma         |                                              X                    X      |          6 |
      Alveolar/Bronchiolar Carcinoma       |    X                                   X                                 |          3 |
      Alveolar/Bronchiolar Carcinoma,      |                                                                          |            |
          Multiple                         |                                                                         X|          1 |
      Carcinoma, Metastatic, Harderian     |                                                                          |            |
          Gland                            |                                                                          |          1 |
      Carcinoma, Metastatic, Thyroid Gland |                X                                                         |          1 |
      Hepatocellular Carcinoma, Metastatic,|                                                                          |            |
           Liver                           |                         X                                                |          4 |
      Artery, Fibrous Histiocytoma         |                                                                X         |          1 |
      Artery, Mediastinum, Fibrous         |                                                                          |            |
          Histiocytoma                     |                                                                X         |          1 |
      Mediastinum, Alveolar/Bronchiolar    |                                                                          |            |
          Carcinoma, Metastatic, Lung      |                                        X                                 |          1 |
                                            __________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Ear                                     |                                                                          |   1        |
                                            __________________________________________________________________________|____________|
   Eye                                     |                                                                          |   1        |
                                            __________________________________________________________________________|____________|
   Harderian Gland                         |       +                                         +                        |   3        |
      Adenoma                              |                                                 X                        |          1 |
      Carcinoma                            |                                                                          |          1 |
      Sarcoma                              |       X                                                                  |          1 |
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +|  48        |
      Artery, Fibrous Histiocytoma         |                                                                X         |          1 |
 __________________________________________________________________________________________________________________________________ 
 SYSTEMIC LESIONS                          |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  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  50                                                               
NTP Experiment-Test: 60968-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 03/17/97  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 18:22:07  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 7| 4| 7| 4| 7| 5| 7| 7| 5| 3| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7|            |
                             DAY ON TEST   | 3| 3| 3| 3| 3| 3| 1| 3| 4| 3| 6| 3| 3| 3| 2| 3| 1| 3| 7| 3| 3| 3| 3| 2| 3|            |
                                           | 3| 4| 3| 3| 3| 3| 0| 3| 8| 4| 0| 3| 4| 5| 2| 3| 1| 3| 2| 3| 4| 3| 3| 8| 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   | 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      |
    1000 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|            |
 __________________________________________________________________________________________________________________________________ 
 SYSTEMIC LESIONS - cont                   |                                                                          |            |
                                           |                                                                          |            |
      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  51                                                               
NTP Experiment-Test: 60968-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 03/17/97  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 18:22:07  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 5| 7| 7| 7| 6| 5| 7| 7| 7| 6| 6| 4| 7| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7|             
                             DAY ON TEST   | 3| 3| 8| 3| 2| 3| 5| 9| 3| 3| 3| 3| 4| 1| 3| 3| 3| 2| 3| 3| 7| 3| 3| 3| 3|             
                                           | 3| 3| 8| 3| 3| 3| 8| 7| 4| 4| 4| 9| 9| 5| 5| 3| 4| 3| 3| 3| 0| 5| 3| 3| 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 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|             
    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                             | +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  +  +  A  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  +  +  A  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |             X                                                            |             
                                            __________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Carcinoma, Metastatic, Parathyroid   |                                                                          |             
          Gland                            |       X                                                                  |             
      Hepatocellular Carcinoma             |                   X              X  X                             X      |             
      Hepatocellular Carcinoma, Multiple   |             X                                      X                     |             
      Hepatocellular Adenoma               |                                  X  X                                   X|             
      Hepatocellular Adenoma, Multiple     |                                                             X            |             
      Lymphoma Malignant                   |             X                                                            |             
                                            __________________________________________________________________________|             
   Mesentery                               |                   +                                +                     |             
      Hepatocellular Carcinoma, Metastatic,|                                                                          |             
           Liver                           |                                                    X                     |             
                                            __________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                                                                          |             
                                            __________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                                                                          |             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Carcinoma, Metastatic, Parathyroid   |                                                                          |             
          Gland                            |       X                                                                  |             
      Capsule, Adenoma                     |                                                       X                  |             
                                            __________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Pheochromocytoma Benign              |                                                                          |             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Adenoma                              |                                                                      X   |             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       | +  +  +  +  +  +  +  M  +  I  +  +  +  +  +  +  M  +  M  +  +  +  M  +  +|             
      Carcinoma                            |       X                                                                  |             
                                            __________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             

                                                             Page  52                                                               
NTP Experiment-Test: 60968-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 03/17/97  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 18:22:07  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 5| 7| 7| 7| 6| 5| 7| 7| 7| 6| 6| 4| 7| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7|             
                             DAY ON TEST   | 3| 3| 8| 3| 2| 3| 5| 9| 3| 3| 3| 3| 4| 1| 3| 3| 3| 2| 3| 3| 7| 3| 3| 3| 3|             
                                           | 3| 3| 8| 3| 3| 3| 8| 7| 4| 4| 4| 9| 9| 5| 5| 3| 4| 3| 3| 3| 0| 5| 3| 3| 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 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|             
    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                   |                                                                          |             
                                           |                                                                          |             
      Follicular Cell, Adenoma             | X  X                                               X           X         |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leiomyoma                            |                X                                                         |             
                                            __________________________________________________________________________|             
   Penis                                   | +                                   +                                    |             
                                            __________________________________________________________________________|             
   Preputial Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Prostate                                | +  +  +  +  +  +  +  +  +  +  +  +  I  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Carcinoma, Metastatic, Parathyroid   |                                                                          |             
          Gland                            |       X                                                                  |             
      Lymphoma Malignant                   |                                                                          |             
                                            __________________________________________________________________________|             
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Interstitial Cell, Adenoma           |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Carcinoma, Metastatic, Parathyroid   |                                                                          |             
          Gland                            |       X                                                                  |             
      Lymphoma Malignant                   |             X                                                            |             
                                            __________________________________________________________________________|             
   Lymph Node                              |                                                             +  +         |             
      Lumbar, Lymphoma Malignant           |                                                             X            |             
      Pancreatic, Lymphoma Malignant       |                                                                X         |             
      Renal, Lymphoma Malignant            |                                                             X            |             
                                            __________________________________________________________________________|             
   Lymph Node, Bronchial                   | +  +  +  M  +  +  +  +  +  +  M  +  M  +  +  +  M  +  +  M  +  +  +  +  +|             
      Lymphoma Malignant                   |                                                             X            |             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  M  +  +  +  +  M  +  M  +  +  +  +  M  M  +  M  +  +  +  M  +  +  +  +|             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  M  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |             X                                         X     X            |             
                                            __________________________________________________________________________|             
   Lymph Node, Mediastinal                 | +  M  +  +  +  +  +  M  M  +  M  +  +  M  M  +  M  +  M  +  +  M  +  M  M|             
      Lymphoma Malignant                   |             X                                               X            |             
                                            __________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |             X                                               X  X         |             
                                            __________________________________________________________________________|             
   Thymus                                  | +  M  M  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|             
                                            __________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Subcutaneous Tissue, Hemangiosarcoma |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
 _____________________________________________________________________________________________________________________|             

                                                             Page  53                                                               
NTP Experiment-Test: 60968-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 03/17/97  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 18:22:07  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 5| 7| 7| 7| 6| 5| 7| 7| 7| 6| 6| 4| 7| 7| 7| 7| 7| 7| 6| 7| 7| 7| 7|             
                             DAY ON TEST   | 3| 3| 8| 3| 2| 3| 5| 9| 3| 3| 3| 3| 4| 1| 3| 3| 3| 2| 3| 3| 7| 3| 3| 3| 3|             
                                           | 3| 3| 8| 3| 3| 3| 8| 7| 4| 4| 4| 9| 9| 5| 5| 3| 4| 3| 3| 3| 0| 5| 3| 3| 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 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|             
    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|             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM - cont             |                                                                          |             
                                           |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Larynx                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Carcinoma, Metastatic, Parathyroid   |                                                                          |             
          Gland                            |       X                                                                  |             
                                            __________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Alveolar/Bronchiolar Adenoma         |    X                                         X              X            |             
      Alveolar/Bronchiolar Adenoma,        |                                                                          |             
          Multiple                         |                                                                          |             
      Alveolar/Bronchiolar Carcinoma       | X                                   X        X                          X|             
      Carcinoma, Metastatic, Parathyroid   |                                                                          |             
          Gland                            |       X                                                                  |             
      Hepatocellular Carcinoma, Metastatic,|                                                                          |             
           Liver                           |             X                    X                                       |             
      Lymphoma Malignant                   |             X                                                            |             
                                            __________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Carcinoma, Metastatic, Parathyroid   |                                                                          |             
          Gland                            |       X                                                                  |             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Harderian Gland                         |                +                                                         |             
      Adenoma                              |                X                                                         |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Carcinoma, Metastatic, Parathyroid   |                                                                          |             
          Gland                            |       X                                                                  |             
      Hepatocellular Carcinoma, Metastatic,|                                                                          |             
           Liver                           |                                                    X                     |             
      Lymphoma Malignant                   |             X                                                            |             
                                            __________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Carcinoma, Metastatic, Parathyroid   |                                                                          |             
          Gland                            |       X                                                                  |             
 _____________________________________________________________________________________________________________________|             
 SYSTEMIC LESIONS                          |                                                                          |             
                                            __________________________________________________________________________|             
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lymphoma Malignant                   |             X                                         X     X  X         |             
 _____________________________________________________________________________________________________________________|             

                                                             Page  54                                                               
NTP Experiment-Test: 60968-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 03/17/97  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 18:22:07  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 6| 7| 7| 6| 7| 7| 6| 7| 6| 5| 7| 7| 7| 7| 7| 6| 7| 6| 4| 7| 7| 6| 5| 7| 7|            |
                             DAY ON TEST   | 7| 3| 3| 5| 3| 3| 6| 3| 9| 7| 3| 3| 3| 3| 3| 5| 3| 9| 9| 3| 3| 1| 4| 0| 3|            |
                                           | 9| 4| 5| 3| 5| 4| 5| 4| 0| 1| 3| 4| 5| 3| 3| 3| 3| 1| 9| 3| 5| 6| 7| 9| 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   | 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      |
    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  M  +  +  +  +  A  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  44        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
                                            __________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  A  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  46        |
                                            __________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  A  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  46        |
                                            __________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
      Lymphoma Malignant                   |                   X                                                      |          2 |
                                            __________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Carcinoma, Metastatic, Parathyroid   |                                                                          |            |
          Gland                            |                                                                          |          1 |
      Hepatocellular Carcinoma             |    X                                            X           X     X      |          8 |
      Hepatocellular Carcinoma, Multiple   |          X                             X     X                           |          5 |
      Hepatocellular Adenoma               |                                  X  X              X                     |          6 |
      Hepatocellular Adenoma, Multiple     |                                                                          |          1 |
      Lymphoma Malignant                   |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Mesentery                               |                                                                   +      |   3        |
      Hepatocellular Carcinoma, Metastatic,|                                                                          |            |
           Liver                           |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Lymphoma Malignant                   |                         X                                                |          1 |
                                            __________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Lymphoma Malignant                   |                         X                                                |          1 |
                                            __________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Lymphoma Malignant                   |                         X                                                |          1 |
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Carcinoma, Metastatic, Parathyroid   |                                                                          |            |
          Gland                            |                                                                          |          1 |
      Capsule, Adenoma                     |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Pheochromocytoma Benign              |                                                                X         |          1 |
                                            __________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  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  55                                                               
NTP Experiment-Test: 60968-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 03/17/97  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 18:22:07  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 6| 7| 7| 6| 7| 7| 6| 7| 6| 5| 7| 7| 7| 7| 7| 6| 7| 6| 4| 7| 7| 6| 5| 7| 7|            |
                             DAY ON TEST   | 7| 3| 3| 5| 3| 3| 6| 3| 9| 7| 3| 3| 3| 3| 3| 5| 3| 9| 9| 3| 3| 1| 4| 0| 3|            |
                                           | 9| 4| 5| 3| 5| 4| 5| 4| 0| 1| 3| 4| 5| 3| 3| 3| 3| 1| 9| 3| 5| 6| 7| 9| 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   | 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      |
    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                   |                                                                          |            |
                                           |                                                                          |            |
      Adenoma                              |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Parathyroid Gland                       | +  +  +  +  +  +  +  M  +  M  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +|  42        |
      Carcinoma                            |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                            __________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Follicular Cell, Adenoma             |                                     X                                    |          5 |
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
                                           |                                                                          |            |
    None                                   |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leiomyoma                            |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Penis                                   |                                                                          |   2        |
                                            __________________________________________________________________________|____________|
   Preputial Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Prostate                                | +  +  +  +  +  +  +  +  +  I  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
                                            __________________________________________________________________________|____________|
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Carcinoma, Metastatic, Parathyroid   |                                                                          |            |
          Gland                            |                                                                          |          1 |
      Lymphoma Malignant                   |                         X                                                |          1 |
                                            __________________________________________________________________________|____________|
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Interstitial Cell, Adenoma           |                      X                                                   |          1 |
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Carcinoma, Metastatic, Parathyroid   |                                                                          |            |
          Gland                            |                                                                          |          1 |
      Lymphoma Malignant                   |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Lymph Node                              |                         +                                      +         |   4        |
      Lumbar, Lymphoma Malignant           |                                                                          |          1 |
      Pancreatic, Lymphoma Malignant       |                         X                                                |          2 |
      Renal, Lymphoma Malignant            |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Lymph Node, Bronchial                   | M  +  +  M  +  M  M  +  +  +  M  M  +  +  M  +  M  M  M  +  +  +  M  +  +|  34        |
      Lymphoma Malignant                   |                         X                                                |          2 |
                                            __________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | +  M  +  +  M  +  M  M  M  M  +  M  +  M  +  +  +  +  M  +  M  +  +  M  M|  31        |
                                            __________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +|  47        |
      Lymphoma Malignant                   |                         X                                                |          4 |
                                            __________________________________________________________________________|____________|
   Lymph Node, Mediastinal                 | M  +  +  +  +  +  +  +  +  +  +  +  +  +  M  M  +  +  +  +  +  +  M  +  M|  34        |
      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  56                                                               
NTP Experiment-Test: 60968-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 03/17/97  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 18:22:07  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 6| 7| 7| 6| 7| 7| 6| 7| 6| 5| 7| 7| 7| 7| 7| 6| 7| 6| 4| 7| 7| 6| 5| 7| 7|            |
                             DAY ON TEST   | 7| 3| 3| 5| 3| 3| 6| 3| 9| 7| 3| 3| 3| 3| 3| 5| 3| 9| 9| 3| 3| 1| 4| 0| 3|            |
                                           | 9| 4| 5| 3| 5| 4| 5| 4| 0| 1| 3| 4| 5| 3| 3| 3| 3| 1| 9| 3| 5| 6| 7| 9| 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   | 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      |
    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               |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Lymphoma Malignant                   |                         X                                                |          4 |
                                            __________________________________________________________________________|____________|
   Thymus                                  | M  +  +  +  M  +  +  +  +  M  +  +  M  M  +  +  +  M  +  +  +  +  +  +  +|  36        |
      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                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Subcutaneous Tissue, Hemangiosarcoma |                      X                                                   |          1 |
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Larynx                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Carcinoma, Metastatic, Parathyroid   |                                                                          |            |
          Gland                            |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Alveolar/Bronchiolar Adenoma         |             X                                                            |          4 |
      Alveolar/Bronchiolar Adenoma,        |                                                                          |            |
          Multiple                         |                                                          X               |          1 |
      Alveolar/Bronchiolar Carcinoma       |                                                       X              X   |          6 |
      Carcinoma, Metastatic, Parathyroid   |                                                                          |            |
          Gland                            |                                                                          |          1 |
      Hepatocellular Carcinoma, Metastatic,|                                                                          |            |
           Liver                           |    X                                   X     X                           |          5 |
      Lymphoma Malignant                   |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Carcinoma, Metastatic, Parathyroid   |                                                                          |            |
          Gland                            |                                                                          |          1 |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Harderian Gland                         |                                  +                                       |   2        |
      Adenoma                              |                                  X                                       |          2 |
 _____________________________________________________________________________________________________________________|            |
 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  57                                                               
NTP Experiment-Test: 60968-02                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                          ISOBUTYRALDEHYDE                                     Date: 03/17/97  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 18:22:07  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 6| 7| 7| 6| 7| 7| 6| 7| 6| 5| 7| 7| 7| 7| 7| 6| 7| 6| 4| 7| 7| 6| 5| 7| 7|            |
                             DAY ON TEST   | 7| 3| 3| 5| 3| 3| 6| 3| 9| 7| 3| 3| 3| 3| 3| 5| 3| 9| 9| 3| 3| 1| 4| 0| 3|            |
                                           | 9| 4| 5| 3| 5| 4| 5| 4| 0| 1| 3| 4| 5| 3| 3| 3| 3| 1| 9| 3| 5| 6| 7| 9| 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   | 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      |
    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                     |                                                                          |            |
                                           |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Carcinoma, Metastatic, Parathyroid   |                                                                          |            |
          Gland                            |                                                                          |          1 |
      Hepatocellular Carcinoma, Metastatic,|                                                                          |            |
           Liver                           |                                                                          |          1 |
      Lymphoma Malignant                   |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Carcinoma, Metastatic, Parathyroid   |                                                                          |            |
          Gland                            |                                                                          |          1 |
 __________________________________________________________________________________________________________________________________ 
 SYSTEMIC LESIONS                          |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Lymphoma Malignant                   |                   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                  

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