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TDMS Study 05158-03 Pathology Tables

NTP Experiment-Test: 05158-03  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                        MOLYBDENUM TRIOXIDE                                    Date: 04/04/96
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 01:54:07




       Facility:  Battelle Northwest

       Chemical CAS #:  0001313-27-5

       Lock Date:  08/06/93

       Cage Range:  All

       Reasons For Removal:    All

       Removal Date Range:     All

       Treatment Groups:       Include All




































a  Number of animals examined microscopically at site and number of animals with lesion

                                                              Page   1


NTP Experiment-Test: 05158-03  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                        MOLYBDENUM TRIOXIDE                                    Date: 04/04/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 01:54:07  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS FEMALE                   CONTROL      10 MG/M3     30 MG/M3     100                                       
                                                                                          MG/M3                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
DISPOSITION SUMMARY                                                                                                                 

  Animals Initially in Study                          50           50           50           50                                     
  Early Deaths                                                                                                                      
    Moribund Sacrifice                                18           25           23           23                                     
    Natural Death                                      4            1            3            4                                     
  Survivors                                                                                                                         
    Moribund Sacrifice                                                                        1                                     
    Terminal Sacrifice                                28           24           24           22                                     

  Animals Examined Microscopically                    50           50           50           50                                     
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ALIMENTARY SYSTEM                                                                                                                  
                                                                                                                                    
   Intestine Large, Colon                             (49)         (49)         (48)         (48)                                   
      Sarcoma                                          1 (2%)                                                                       
   Intestine Large, Cecum                             (49)         (49)         (47)         (48)                                   
   Intestine Small, Duodenum                          (49)         (49)         (48)         (49)                                   
   Intestine Small, Jejunum                           (47)         (49)         (47)         (47)                                   
   Intestine Small, Ileum                             (48)         (49)         (47)         (48)                                   
   Liver                                              (50)         (49)         (50)         (50)                                   
      Hepatocellular Adenoma                           1 (2%)                                                                       
   Mesentery                                          (3)          (11)         (5)          (8)                                    
   Oral Mucosa                                        (1)                                                                           
      Gingival, Squamous Cell Carcinoma                1 (100%)                                                                     
   Pancreas                                           (49)         (49)         (50)         (50)                                   
   Salivary Glands                                    (50)         (50)         (50)         (50)                                   
   Stomach, Forestomach                               (50)         (49)         (50)         (50)                                   
   Stomach, Glandular                                 (49)         (49)         (50)         (50)                                   
   Tongue                                             (1)                       (1)                                                 
      Squamous Cell Papilloma                          1 (100%)                  1 (100%)                                           
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 CARDIOVASCULAR SYSTEM                                                                                                              
                                                                                                                                    
   Heart                                              (50)         (50)         (50)         (50)                                   
      Schwannoma Benign                                                          1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ENDOCRINE SYSTEM                                                                                                                   
                                                                                                                                    
   Adrenal Cortex                                     (49)         (49)         (50)         (50)                                   
      Adenoma                                          1 (2%)                                                                       
   Adrenal Medulla                                    (49)         (49)         (50)         (50)                                   
      Pheochromocytoma Complex                         1 (2%)                                                                       
      Pheochromocytoma Benign                          3 (6%)                    4 (8%)       6 (12%)                               

                                                             Page   2                                                               
NTP Experiment-Test: 05158-03  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                        MOLYBDENUM TRIOXIDE                                    Date: 04/04/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 01:54:07  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS FEMALE                   CONTROL      10 MG/M3     30 MG/M3     100                                       
                                                                                          MG/M3                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ENDOCRINE SYSTEM - cont                                                                                                             
      Bilateral, Pheochromocytoma Benign               2 (4%)                                                                       
   Islets, Pancreatic                                 (49)         (49)         (50)         (50)                                   
      Adenoma                                          1 (2%)                    1 (2%)       1 (2%)                                
      Carcinoma                                                                               1 (2%)                                
   Pituitary Gland                                    (49)         (50)         (50)         (50)                                   
      Pars Distalis, Adenoma                          43 (88%)     39 (78%)     40 (80%)     38 (76%)                               
   Thyroid Gland                                      (49)         (49)         (50)         (50)                                   
      C-Cell, Adenoma                                  3 (6%)       8 (16%)      6 (12%)      3 (6%)                                
      C-Cell, Carcinoma                                3 (6%)       1 (2%)       1 (2%)       2 (4%)                                
      Follicular Cell, Adenoma                         1 (2%)       1 (2%)                                                          
      Follicular Cell, Carcinoma                                    1 (2%)                    1 (2%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENERAL BODY SYSTEM                                                                                                                
                                                                                                                                    
   None                                                                                                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENITAL SYSTEM                                                                                                                     
                                                                                                                                    
   Clitoral Gland                                     (44)         (48)         (47)         (47)                                   
      Adenoma                                          2 (5%)       6 (13%)      5 (11%)      1 (2%)                                
      Carcinoma                                        1 (2%)       1 (2%)       5 (11%)      2 (4%)                                
   Ovary                                              (50)         (50)         (50)         (50)                                   
      Granulosa Cell Tumor Malignant                   1 (2%)       1 (2%)                                                          
      Granulosa-Theca Tumor Malignant                  1 (2%)                                                                       
   Uterus                                             (50)         (49)         (50)         (50)                                   
      Deciduoma Benign                                                           1 (2%)                                             
      Leiomyoma                                                                               1 (2%)                                
      Polyp Stromal                                    6 (12%)      8 (16%)      6 (12%)      8 (16%)                               
      Polyp Stromal, Multiple                                                    2 (4%)                                             
      Sarcoma Stromal                                                            1 (2%)       2 (4%)                                
   Vagina                                                                                    (1)                                    
      Schwannoma Malignant                                                                    1 (100%)                              
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 HEMATOPOIETIC SYSTEM                                                                                                               
                                                                                                                                    
   Bone Marrow                                        (50)         (49)         (50)         (50)                                   
   Lymph Node                                         (3)          (8)          (2)          (2)                                    
   Lymph Node, Bronchial                              (44)         (36)         (37)         (40)                                   
   Lymph Node, Mandibular                             (46)         (41)         (47)         (43)                                   
      Carcinoma, Metastatic, Zymbal's Gland                                      1 (2%)                                             
   Lymph Node, Mesenteric                             (49)         (49)         (50)         (50)                                   
   Lymph Node, Mediastinal                            (41)         (41)         (43)         (48)                                   
   Spleen                                             (49)         (49)         (50)         (50)                                   
   Thymus                                             (48)         (45)         (47)         (46)                                   

                                                             Page   3                                                               
NTP Experiment-Test: 05158-03  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                        MOLYBDENUM TRIOXIDE                                    Date: 04/04/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 01:54:07  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS FEMALE                   CONTROL      10 MG/M3     30 MG/M3     100                                       
                                                                                          MG/M3                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
HEMATOPOIETIC SYSTEM - cont                                                                                                         
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 INTEGUMENTARY SYSTEM                                                                                                               
                                                                                                                                    
   Mammary Gland                                      (50)         (50)         (49)         (50)                                   
      Adenoma                                                       3 (6%)       3 (6%)       1 (2%)                                
      Carcinoma                                        1 (2%)       2 (4%)       2 (4%)       3 (6%)                                
      Fibroadenoma                                    16 (32%)     24 (48%)     22 (45%)     13 (26%)                               
      Fibroadenoma, Multiple                           6 (12%)      8 (16%)      6 (12%)      5 (10%)                               
   Skin                                               (50)         (49)         (50)         (50)                                   
      Basal Cell Carcinoma                             1 (2%)                                                                       
      Squamous Cell Papilloma                          1 (2%)                                                                       
      Subcutaneous Tissue, Lipoma                                                1 (2%)                                             
      Subcutaneous Tissue, Melanoma Malignant                                                 1 (2%)                                
      Subcutaneous Tissue, Schwannoma Malignant        1 (2%)                                                                       
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 MUSCULOSKELETAL SYSTEM                                                                                                             
                                                                                                                                    
   Skeletal Muscle                                                                           (1)                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 NERVOUS SYSTEM                                                                                                                     
                                                                                                                                    
   Brain                                              (50)         (50)         (50)         (50)                                   
      Astrocytoma Benign                                            1 (2%)                                                          
      Carcinoma, Metastatic, Zymbal's Gland                                      1 (2%)                                             
      Oligodendroglioma Benign                                                   1 (2%)                                             
      Meninges, Granular Cell Tumor Benign                                       1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 RESPIRATORY SYSTEM                                                                                                                 
                                                                                                                                    
   Larynx                                             (49)         (49)         (49)         (50)                                   
   Lung                                               (50)         (50)         (50)         (50)                                   
      Alveolar/Bronchiolar Adenoma                                  1 (2%)                    2 (4%)                                
      Alveolar/Bronchiolar Carcinoma                                1 (2%)                                                          
      Carcinoma, Metastatic, Zymbal's Gland                         1 (2%)       1 (2%)                                             
      Melanoma Malignant, Metastatic, Skin                                                    1 (2%)                                
      Sarcoma                                                                                 1 (2%)                                
      Squamous Cell Carcinoma                          1 (2%)                                                                       
   Nose                                               (48)         (49)         (50)         (50)                                   
____________________________________________________________________________________________________________________________________
                                                                                                                                    

                                                             Page   4                                                               
NTP Experiment-Test: 05158-03  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                        MOLYBDENUM TRIOXIDE                                    Date: 04/04/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 01:54:07  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS FEMALE                   CONTROL      10 MG/M3     30 MG/M3     100                                       
                                                                                          MG/M3                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SPECIAL SENSES SYSTEM                                                                                                              
                                                                                                                                    
   Zymbal's Gland                                     (1)          (1)          (2)                                                 
      Carcinoma                                        1 (100%)     1 (100%)     2 (100%)                                           
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 URINARY SYSTEM                                                                                                                     
                                                                                                                                    
   Kidney                                             (50)         (49)         (50)         (50)                                   
      Lipoma                                                        1 (2%)       1 (2%)                                             
      Renal Tubule, Adenoma                                                                   1 (2%)                                
      Renal Tubule, Carcinoma                                       1 (2%)       1 (2%)                                             
   Urinary Bladder                                    (49)         (50)         (50)         (50)                                   
      Transitional Epithelium, Papilloma                                                      1 (2%)                                
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SYSTEMIC LESIONS                                                                                                                   

   Multiple Organs                                   *(50)        *(50)        *(50)        *(50)                                   
      Leukemia Mononuclear                            18 (36%)     19 (38%)     13 (26%)     20 (40%)                               
      Lymphoma Malignant                                            1 (2%)                                                          
____________________________________________________________________________________________________________________________________

                                                                                                                                    
     *   Number of animals with any tissue examined microscopically                                                                 

                                                             Page   5                                                               
NTP Experiment-Test: 05158-03  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                        MOLYBDENUM TRIOXIDE                                    Date: 04/04/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 01:54:07  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS FEMALE                   CONTROL      10 MG/M3     30 MG/M3     100                                       
                                                                                          MG/M3                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
TUMOR SUMMARY                                                                                                                       
                                                                                                                                    
   Total Animals with Primary Neoplasms (b)            48          50          49          49                                       
     Total Primary Neoplasms                          119         129         127         115                                       
                                                                                                                                    
   Total Animals with Benign Neoplasms                 45          49          49          47                                       
     Total Benign Neoplasms                            87         100         102          81                                       
                                                                                                                                    
   Total Animals with Malignant Neoplasms              28          23          23          30                                       
     Total Malignant Neoplasms                         32          29          25          34                                       
                                                                                                                                    
   Total Animals with Metastatic Neoplasms                          1           1           1                                       
     Total Metastatic Neoplasm                                      1           3           1                                       
                                                                                                                                    
   Total Animals with Malignant Neoplasms                                                                                           
   Uncertain Primary Site                                                                                                           
                                                                                                                                    
   Total Animals with Neoplasms Uncertain-                                                                                          
   Benign or Malignant                                                                                                              
     Total Uncertain Neoplasms                                                                                                      
                                                                                                                                    

____________________________________________________________________________________________________________________________________
a  Number of animals examined microscopically at site and number of animals with lesion                                             
b  Primary tumors: all tumors except metastatic tumors                                                                              

                                                             Page   6                                                               
NTP Experiment-Test: 05158-03  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                        MOLYBDENUM TRIOXIDE                                    Date: 04/04/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 01:54:07  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS MALE                     CONTROL      10 MG/M3     30 MG/M3     100                                       
                                                                                          MG/M3                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
DISPOSITION SUMMARY                                                                                                                 

  Animals Initially in Study                          50           50           50           50                                     
  Early Deaths                                                                                                                      
    Natural Death                                      4            5            3            5                                     
    Moribund Sacrifice                                29           35           31           28                                     
  Survivors                                                                                                                         
    Terminal Sacrifice                                16           10           16           17                                     
    Moribund Sacrifice                                 1                                                                            

  Animals Examined Microscopically                    50           50           50           50                                     
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ALIMENTARY SYSTEM                                                                                                                  
                                                                                                                                    
   Intestine Large, Colon                             (49)         (46)         (50)         (50)                                   
   Intestine Large, Rectum                            (49)         (49)         (50)         (49)                                   
   Intestine Large, Cecum                             (48)         (47)         (48)         (49)                                   
      Leiomyoma                                                                               1 (2%)                                
   Intestine Small, Duodenum                          (49)         (48)         (49)         (49)                                   
      Carcinoma                                                     1 (2%)       1 (2%)                                             
   Intestine Small, Jejunum                           (48)         (48)         (48)         (48)                                   
   Intestine Small, Ileum                             (48)         (47)         (46)         (49)                                   
   Liver                                              (50)         (50)         (50)         (50)                                   
      Hepatocellular Carcinoma                         2 (4%)       1 (2%)       1 (2%)       2 (4%)                                
      Hepatocellular Adenoma                                        1 (2%)                    1 (2%)                                
   Mesentery                                          (10)         (9)          (9)          (11)                                   
   Oral Mucosa                                        (1)                       (1)          (1)                                    
      Pharyngeal, Squamous Cell Carcinoma              1 (100%)                                                                     
      Pharyngeal, Squamous Cell Papilloma                                        1 (100%)     1 (100%)                              
   Pancreas                                           (50)         (50)         (50)         (50)                                   
      Adenoma                                          1 (2%)       1 (2%)       2 (4%)       1 (2%)                                
      Mixed Tumor Benign                               1 (2%)                                 1 (2%)                                
   Salivary Glands                                    (50)         (50)         (50)         (50)                                   
   Stomach, Forestomach                               (50)         (50)         (50)         (50)                                   
   Stomach, Glandular                                 (50)         (50)         (50)         (50)                                   
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 CARDIOVASCULAR SYSTEM                                                                                                              
                                                                                                                                    
   Heart                                              (50)         (50)         (50)         (50)                                   
      Alveolar/Bronchiolar Carcinoma, Metastatic,                                                                                   
           Lung                                                                               1 (2%)                                
      Hemangioma                                                                 1 (2%)                                             
      Schwannoma Malignant                                                       1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    

                                                             Page   7                                                               
NTP Experiment-Test: 05158-03  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                        MOLYBDENUM TRIOXIDE                                    Date: 04/04/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 01:54:07  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS MALE                     CONTROL      10 MG/M3     30 MG/M3     100                                       
                                                                                          MG/M3                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ENDOCRINE SYSTEM                                                                                                                   
                                                                                                                                    
   Adrenal Cortex                                     (50)         (50)         (50)         (50)                                   
      Adenoma                                                                    2 (4%)                                             
   Adrenal Medulla                                    (50)         (50)         (50)         (50)                                   
      Pheochromocytoma Malignant                       2 (4%)       1 (2%)       1 (2%)       2 (4%)                                
      Pheochromocytoma Complex                                      1 (2%)                                                          
      Pheochromocytoma Benign                         15 (30%)      4 (8%)      15 (30%)     14 (28%)                               
      Bilateral, Pheochromocytoma Benign                            7 (14%)      2 (4%)       3 (6%)                                
   Islets, Pancreatic                                 (50)         (50)         (49)         (49)                                   
      Adenoma                                          3 (6%)       6 (12%)      1 (2%)       4 (8%)                                
      Carcinoma                                        1 (2%)       2 (4%)       2 (4%)       4 (8%)                                
   Parathyroid Gland                                  (47)         (49)         (46)         (49)                                   
      Adenoma                                                                    1 (2%)                                             
   Pituitary Gland                                    (49)         (50)         (50)         (48)                                   
      Pars Distalis, Adenoma                          37 (76%)     39 (78%)     40 (80%)     36 (75%)                               
   Thyroid Gland                                      (50)         (50)         (50)         (50)                                   
      Bilateral, C-Cell, Adenoma                                    2 (4%)       2 (4%)                                             
      C-Cell, Adenoma                                  3 (6%)       3 (6%)       6 (12%)      3 (6%)                                
      C-Cell, Carcinoma                                4 (8%)                    1 (2%)       3 (6%)                                
      Follicular Cell, Adenoma                         1 (2%)       1 (2%)                    1 (2%)                                
      Follicular Cell, Carcinoma                                                 2 (4%)       2 (4%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENERAL BODY SYSTEM                                                                                                                
                                                                                                                                    
   Tissue NOS                                         (1)                                                                           
      Chemodectoma Malignant                           1 (100%)                                                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENITAL SYSTEM                                                                                                                     
                                                                                                                                    
   Epididymis                                         (50)         (50)         (50)         (50)                                   
   Preputial Gland                                    (50)         (50)         (50)         (50)                                   
      Adenoma                                          2 (4%)       3 (6%)       3 (6%)       3 (6%)                                
      Carcinoma                                        3 (6%)       3 (6%)       1 (2%)       1 (2%)                                
   Prostate                                           (50)         (50)         (50)         (50)                                   
      Adenoma, Multiple                                1 (2%)                                                                       
   Seminal Vesicle                                    (50)         (50)         (50)         (50)                                   
   Testes                                             (50)         (50)         (50)         (50)                                   
      Bilateral, Interstitial Cell, Adenoma           30 (60%)     21 (42%)     23 (46%)     30 (60%)                               
      Interstitial Cell, Adenoma                       9 (18%)     11 (22%)     13 (26%)      8 (16%)                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    

                                                             Page   8                                                               
NTP Experiment-Test: 05158-03  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                        MOLYBDENUM TRIOXIDE                                    Date: 04/04/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 01:54:07  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS MALE                     CONTROL      10 MG/M3     30 MG/M3     100                                       
                                                                                          MG/M3                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 HEMATOPOIETIC SYSTEM                                                                                                               
                                                                                                                                    
   Bone Marrow                                        (50)         (50)         (50)         (50)                                   
      Hemangiosarcoma                                               1 (2%)                                                          
      Squamous Cell Carcinoma, Metastatic, Skin                                               1 (2%)                                
   Lymph Node                                         (16)         (17)         (8)          (15)                                   
      Iliac, Squamous Cell Carcinoma, Metastatic,                                                                                   
           Skin                                        1 (6%)                                                                       
   Lymph Node, Bronchial                              (45)         (45)         (42)         (43)                                   
   Lymph Node, Mandibular                             (48)         (48)         (49)         (48)                                   
   Lymph Node, Mesenteric                             (50)         (50)         (50)         (49)                                   
   Lymph Node, Mediastinal                            (48)         (49)         (46)         (48)                                   
   Spleen                                             (50)         (50)         (50)         (50)                                   
      Fibroma                                                                                 2 (4%)                                
      Hemangiosarcoma                                  1 (2%)                                                                       
      Sarcoma                                                                                 1 (2%)                                
   Thymus                                             (45)         (45)         (44)         (44)                                   
      Thymoma Malignant                                                          1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 INTEGUMENTARY SYSTEM                                                                                                               
                                                                                                                                    
   Mammary Gland                                      (30)         (25)         (25)         (27)                                   
      Fibroadenoma                                                               2 (8%)       1 (4%)                                
   Skin                                               (49)         (50)         (49)         (49)                                   
      Basal Cell Adenoma                                                         1 (2%)                                             
      Basal Cell Carcinoma                                          2 (4%)                                                          
      Keratoacanthoma                                  1 (2%)       4 (8%)       1 (2%)       2 (4%)                                
      Squamous Cell Carcinoma                          1 (2%)                                 2 (4%)                                
      Squamous Cell Papilloma                                       1 (2%)                    1 (2%)                                
      Sebaceous Gland, Squamous Cell Papilloma         1 (2%)                                                                       
      Subcutaneous Tissue, Fibroma                     3 (6%)       3 (6%)       3 (6%)       4 (8%)                                
      Subcutaneous Tissue, Fibrosarcoma                                                       1 (2%)                                
      Subcutaneous Tissue, Fibrous Histiocytoma                     1 (2%)                                                          
      Subcutaneous Tissue, Lipoma                                   1 (2%)                                                          
      Subcutaneous Tissue, Sarcoma                                                            1 (2%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 MUSCULOSKELETAL SYSTEM                                                                                                             
                                                                                                                                    
   Bone                                               (50)         (50)         (50)         (50)                                   
      Osteosarcoma                                                  1 (2%)       1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    

                                                             Page   9                                                               
NTP Experiment-Test: 05158-03  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                        MOLYBDENUM TRIOXIDE                                    Date: 04/04/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 01:54:07  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS MALE                     CONTROL      10 MG/M3     30 MG/M3     100                                       
                                                                                          MG/M3                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 NERVOUS SYSTEM                                                                                                                     
                                                                                                                                    
   Brain                                              (50)         (50)         (50)         (50)                                   
      Meningioma Malignant                                          1 (2%)                                                          
      Oligodendroglioma Benign                                                   1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 RESPIRATORY SYSTEM                                                                                                                 
                                                                                                                                    
   Lung                                               (50)         (50)         (50)         (50)                                   
      Alveolar/Bronchiolar Adenoma                                                            3 (6%)                                
      Alveolar/Bronchiolar Carcinoma                                1 (2%)       1 (2%)       1 (2%)                                
      Carcinoma, Metastatic, Thyroid Gland                                       1 (2%)                                             
      Neoplasm NOS                                                  1 (2%)                                                          
      Osteosarcoma, Metastatic, Bone                                1 (2%)                                                          
      Squamous Cell Carcinoma, Metastatic, Skin        1 (2%)                                 1 (2%)                                
      Mediastinum, Alveolar/Bronchiolar Carcinoma,                                                                                  
           Metastatic, Lung                                                                   1 (2%)                                
   Nose                                               (50)         (49)         (49)         (50)                                   
      Carcinoma                                                                  1 (2%)                                             
      Chondroma                                                                               1 (2%)                                
      Squamous Cell Carcinoma, Metastatic, Skin                                               1 (2%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SPECIAL SENSES SYSTEM                                                                                                              
                                                                                                                                    
   Zymbal's Gland                                     (2)                       (1)                                                 
      Carcinoma                                        2 (100%)                  1 (100%)                                           
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 URINARY SYSTEM                                                                                                                     
                                                                                                                                    
   Kidney                                             (50)         (50)         (50)         (50)                                   
      Adenoma                                                       1 (2%)                                                          
      Histiocytic Sarcoma                                                        1 (2%)                                             
      Sarcoma                                                       1 (2%)                                                          
      Renal Tubule, Adenoma                            1 (2%)                    2 (4%)       2 (4%)                                
   Urinary Bladder                                    (50)         (50)         (50)         (50)                                   
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SYSTEMIC LESIONS                                                                                                                   

   Multiple Organs                                   *(50)        *(50)        *(50)        *(50)                                   
      Histiocytic Sarcoma                                                        1 (2%)                                             
      Leukemia Mononuclear                            35 (70%)     31 (62%)     28 (56%)     32 (64%)                               
      Mesothelioma Benign                              3 (6%)       3 (6%)                    1 (2%)                                
      Mesothelioma Malignant                                        1 (2%)                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
     *   Number of animals with any tissue examined microscopically                                                                 

                                                             Page  10                                                               
NTP Experiment-Test: 05158-03  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                        MOLYBDENUM TRIOXIDE                                    Date: 04/04/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 01:54:07  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS MALE                     CONTROL      10 MG/M3     30 MG/M3     100                                       
                                                                                          MG/M3                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
TUMOR SUMMARY                                                                                                                       
                                                                                                                                    
   Total Animals with Primary Neoplasms (b)            50          50          50          49                                       
     Total Primary Neoplasms                          165         162         166         176                                       
                                                                                                                                    
   Total Animals with Benign Neoplasms                 50          48          49          46                                       
     Total Benign Neoplasms                           112         112         122         124                                       
                                                                                                                                    
   Total Animals with Malignant Neoplasms              40          38          34          40                                       
     Total Malignant Neoplasms                         53          49          44          52                                       
                                                                                                                                    
   Total Animals with Metastatic Neoplasms              1           1           1           2                                       
     Total Metastatic Neoplasm                          2           1           1           5                                       
                                                                                                                                    
   Total Animals with Malignant Neoplasms                                                                                           
   Uncertain Primary Site                                                                                                           
                                                                                                                                    
   Total Animals with Neoplasms Uncertain-                                                                                          
   Benign or Malignant                                              1                                                               
     Total Uncertain Neoplasms                                      1                                                               
                                                                                                                                    

____________________________________________________________________________________________________________________________________
a  Number of animals examined microscopically at site and number of animals with lesion                                             
b  Primary tumors: all tumors except metastatic tumors                                                                              

                                                             Page  11                                                               
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