Skip to Main Navigation
Skip to Page Content
Share This:
https://ntp.niehs.nih.gov/go/6811

TDMS Study 05200-06 Pathology Tables

NTP Experiment-Test: 05200-06  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                            NITROMETHANE                                       Date: 04/04/96
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 06:10:52




       Facility:  Battelle Northwest

       Chemical CAS #:  75-52-5

       Lock Date:  06/22/92

       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: 05200-06  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                            NITROMETHANE                                       Date: 04/04/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 06:10:52  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE FEMALE                        CONTROL      188 PPM      375 PPM      750 PPM                                   
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
DISPOSITION SUMMARY                                                                                                                 

  Animals Initially in Study                          50           50           50           50                                     
  Early Deaths                                                                                                                      
    Natural Death                                      7            5            3            2                                     
    Moribund Sacrifice                                16           17           20           12                                     
    Accidently Killed                                  2                         1                                                  
  Survivors                                                                                                                         
    Terminal Sacrifice                                25           27           26           36                                     
    Moribund Sacrifice                                              1                                                               

  Animals Examined Microscopically                    50           50           50           50                                     
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ALIMENTARY SYSTEM                                                                                                                  
                                                                                                                                    
   Gallbladder                                        (40)         (45)         (45)         (46)                                   
   Intestine Large, Colon                             (49)         (48)         (47)         (50)                                   
      Leiomyoma                                                                  1 (2%)                                             
   Intestine Large, Cecum                             (49)         (46)         (47)         (50)                                   
   Intestine Small, Duodenum                          (48)         (43)         (45)         (49)                                   
   Intestine Small, Jejunum                           (47)         (45)         (47)         (48)                                   
   Intestine Small, Ileum                             (47)         (46)         (46)         (49)                                   
   Liver                                              (50)         (49)         (49)         (50)                                   
      Hemangiosarcoma                                  2 (4%)                    2 (4%)                                             
      Hepatocellular Carcinoma                         7 (14%)     14 (29%)      8 (16%)     11 (22%)                               
      Hepatocellular Carcinoma, Multiple               3 (6%)                                 1 (2%)                                
      Hepatocellular Adenoma                          11 (22%)     12 (24%)     13 (27%)     22 (44%)                               
      Hepatocellular Adenoma, Multiple                 3 (6%)      13 (27%)      4 (8%)      13 (26%)                               
      Hepatocholangiocarcinoma                         1 (2%)                                                                       
      Histiocytic Sarcoma                              1 (2%)                    2 (4%)                                             
   Mesentery                                          (7)          (14)         (8)          (11)                                   
      Hemangioma                                                    1 (7%)                    1 (9%)                                
      Hemangiosarcoma                                                            1 (13%)                                            
      Hepatocellular Carcinoma, Metastatic, Liver                   1 (7%)                                                          
      Sarcoma                                                       1 (7%)                                                          
      Sarcoma, Metastatic, Skin                        1 (14%)                                                                      
   Oral Mucosa                                        (1)                                    (1)                                    
      Hepatocholangiocarcinoma, Metastatic, Liver      1 (100%)                                                                     
   Pancreas                                           (50)         (48)         (48)         (50)                                   
      Histiocytic Sarcoma                                                        1 (2%)                                             
   Salivary Glands                                    (49)         (48)         (49)         (50)                                   
      Hemangiosarcoma                                               1 (2%)                                                          
   Stomach, Forestomach                               (50)         (48)         (49)         (50)                                   
      Squamous Cell Papilloma                          1 (2%)       1 (2%)                    2 (4%)                                
   Stomach, Glandular                                 (49)         (48)         (48)         (50)                                   
      Adenoma                                                       1 (2%)                                                          

                                                             Page   2                                                               
NTP Experiment-Test: 05200-06  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                            NITROMETHANE                                       Date: 04/04/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 06:10:52  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE FEMALE                        CONTROL      188 PPM      375 PPM      750 PPM                                   
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ALIMENTARY SYSTEM - cont                                                                                                            
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 CARDIOVASCULAR SYSTEM                                                                                                              
                                                                                                                                    
   Heart                                              (50)         (50)         (50)         (50)                                   
      Hepatocellular Carcinoma, Metastatic, Liver                   1 (2%)                                                          
      Hepatocholangiocarcinoma, Metastatic, Liver      1 (2%)                                                                       
      Histiocytic Sarcoma                              1 (2%)                    1 (2%)                                             
      Pericardium, Hepatocellular Carcinoma,                                                                                        
          Metastatic, Liver                                         1 (2%)                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ENDOCRINE SYSTEM                                                                                                                   
                                                                                                                                    
   Adrenal Cortex                                     (50)         (48)         (49)         (50)                                   
      Capsule, Adenoma                                 1 (2%)                    1 (2%)       1 (2%)                                
   Adrenal Medulla                                    (50)         (48)         (49)         (49)                                   
      Pheochromocytoma Benign                                                    1 (2%)                                             
      Bilateral, Pheochromocytoma Benign                                         1 (2%)                                             
   Islets, Pancreatic                                 (50)         (48)         (47)         (50)                                   
      Adenoma                                                                                 1 (2%)                                
   Parathyroid Gland                                  (33)         (34)         (33)         (34)                                   
      Carcinoma                                        1 (3%)                                                                       
   Pituitary Gland                                    (50)         (46)         (48)         (50)                                   
      Pars Distalis, Adenoma                           9 (18%)     10 (22%)      8 (17%)      4 (8%)                                
      Pars Intermedia, Adenoma                                      1 (2%)                                                          
   Thyroid Gland                                      (50)         (48)         (48)         (50)                                   
      Follicular Cell, Adenoma                         4 (8%)       1 (2%)       1 (2%)       1 (2%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENERAL BODY SYSTEM                                                                                                                
                                                                                                                                    
   None                                                                                                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENITAL SYSTEM                                                                                                                     
                                                                                                                                    
   Ovary                                              (47)         (47)         (48)         (48)                                   
      Cystadenocarcinoma                                                                      1 (2%)                                
      Cystadenoma                                      2 (4%)       1 (2%)                    3 (6%)                                
      Granulosa Cell Tumor Benign                                   2 (4%)                                                          
      Histiocytic Sarcoma                              1 (2%)                                                                       
      Luteoma                                                                                 1 (2%)                                
      Teratoma Benign                                                                         1 (2%)                                
   Uterus                                             (50)         (49)         (49)         (50)                                   
      Adenoma                                          1 (2%)       1 (2%)                    1 (2%)                                
      Deciduoma Benign                                              1 (2%)                                                          

                                                             Page   3                                                               
NTP Experiment-Test: 05200-06  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                            NITROMETHANE                                       Date: 04/04/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 06:10:52  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE FEMALE                        CONTROL      188 PPM      375 PPM      750 PPM                                   
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
GENITAL SYSTEM - cont                                                                                                               
      Hemangioma                                       2 (4%)       5 (10%)                                                         
      Histiocytic Sarcoma                              1 (2%)                    1 (2%)                                             
      Polyp Stromal                                    4 (8%)       2 (4%)       1 (2%)       3 (6%)                                
   Vagina                                             (1)                                                                           
      Histiocytic Sarcoma                              1 (100%)                                                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 HEMATOPOIETIC SYSTEM                                                                                                               
                                                                                                                                    
   Bone Marrow                                        (50)         (48)         (49)         (50)                                   
      Hemangiosarcoma                                  1 (2%)                    2 (4%)                                             
      Histiocytic Sarcoma                              1 (2%)                                                                       
      Mast Cell Tumor Malignant                        1 (2%)                                                                       
      Sarcoma, Metastatic, Skin                                                               1 (2%)                                
   Lymph Node                                         (8)          (6)          (5)          (6)                                    
   Lymph Node, Bronchial                              (39)         (36)         (40)         (40)                                   
      Hepatocellular Carcinoma, Metastatic, Liver                   2 (6%)                                                          
      Hepatocholangiocarcinoma, Metastatic, Liver      1 (3%)                                                                       
   Lymph Node, Mandibular                             (43)         (34)         (38)         (43)                                   
      Histiocytic Sarcoma                              1 (2%)                    1 (3%)                                             
   Lymph Node, Mesenteric                             (48)         (46)         (46)         (48)                                   
      Histiocytic Sarcoma                              1 (2%)                    1 (2%)                                             
   Lymph Node, Mediastinal                            (38)         (37)         (35)         (41)                                   
      Carcinoma, Metastatic, Harderian Gland                                     1 (3%)                                             
      Hepatocellular Carcinoma, Metastatic, Liver                   1 (3%)                                                          
      Hepatocholangiocarcinoma, Metastatic, Liver      1 (3%)                                                                       
      Histiocytic Sarcoma                                                        1 (3%)                                             
   Spleen                                             (50)         (48)         (49)         (50)                                   
      Hemangiosarcoma                                               1 (2%)       1 (2%)                                             
      Histiocytic Sarcoma                                                        2 (4%)                                             
      Mast Cell Tumor Malignant                        1 (2%)                                                                       
   Thymus                                             (43)         (39)         (41)         (47)                                   
      Hepatocellular Carcinoma, Metastatic, Liver                   1 (3%)                                                          
      Hepatocholangiocarcinoma, Metastatic, Liver      1 (2%)                                                                       
      Mast Cell Tumor Malignant                        1 (2%)                                                                       
      Thymoma Benign                                   1 (2%)                                                                       
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 INTEGUMENTARY SYSTEM                                                                                                               
                                                                                                                                    
   Mammary Gland                                      (50)         (48)         (49)         (50)                                   
      Adenoma                                                                    1 (2%)                                             
      Carcinoma                                        2 (4%)       2 (4%)       2 (4%)                                             
   Skin                                               (49)         (47)         (50)         (50)                                   
      Squamous Cell Carcinoma                                                    1 (2%)                                             
      Subcutaneous Tissue, Hemangiosarcoma                                       2 (4%)                                             
      Subcutaneous Tissue, Sarcoma                     1 (2%)       1 (2%)       1 (2%)       2 (4%)                                

                                                             Page   4                                                               
NTP Experiment-Test: 05200-06  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                            NITROMETHANE                                       Date: 04/04/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 06:10:52  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE FEMALE                        CONTROL      188 PPM      375 PPM      750 PPM                                   
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 MUSCULOSKELETAL SYSTEM                                                                                                             
                                                                                                                                    
   Bone                                               (50)         (50)         (50)         (50)                                   
      Hemangiosarcoma                                               1 (2%)       2 (4%)                                             
      Osteosarcoma                                                               1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 NERVOUS SYSTEM                                                                                                                     
                                                                                                                                    
   Brain                                              (50)         (50)         (49)         (50)                                   
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 RESPIRATORY SYSTEM                                                                                                                 
                                                                                                                                    
   Larynx                                             (49)         (48)         (49)         (50)                                   
   Lung                                               (50)         (50)         (49)         (50)                                   
      Alveolar/Bronchiolar Adenoma                     3 (6%)       2 (4%)       2 (4%)       8 (16%)                               
      Alveolar/Bronchiolar Adenoma, Multiple                        1 (2%)                    1 (2%)                                
      Alveolar/Bronchiolar Carcinoma                                3 (6%)       5 (10%)                                            
      Alveolar/Bronchiolar Carcinoma, Multiple                                                3 (6%)                                
      Carcinoma, Metastatic, Harderian Gland                                     2 (4%)                                             
      Hepatocellular Carcinoma, Metastatic, Liver      2 (4%)       5 (10%)                   3 (6%)                                
      Hepatocholangiocarcinoma, Metastatic, Liver      1 (2%)                                                                       
      Histiocytic Sarcoma                              1 (2%)                    2 (4%)                                             
      Osteosarcoma, Metastatic, Bone                                             1 (2%)                                             
      Sarcoma, Metastatic, Skin                                                               1 (2%)                                
      Mediastinum, Hemangioma                          1 (2%)                                                                       
      Mediastinum, Hemangiosarcoma                     1 (2%)                                                                       
      Mediastinum, Hepatocellular Carcinoma,                                                                                        
          Metastatic, Liver                                         2 (4%)                                                          
      Mediastinum, Hepatocholangiocarcinoma,                                                                                        
          Metastatic, Liver                            1 (2%)                                                                       
      Mediastinum, Mast Cell Tumor Malignant           1 (2%)                                                                       
   Nose                                               (50)         (49)         (50)         (50)                                   
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SPECIAL SENSES SYSTEM                                                                                                              
                                                                                                                                    
   Harderian Gland                                    (49)         (49)         (50)         (50)                                   
      Adenoma                                          4 (8%)       6 (12%)     15 (30%)     16 (32%)                               
      Adenoma, Multiple                                1 (2%)       1 (2%)       1 (2%)       3 (6%)                                
      Carcinoma                                        1 (2%)       2 (4%)       4 (8%)       2 (4%)                                
      Carcinoma, Multiple                                                                     1 (2%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    

                                                             Page   5                                                               
NTP Experiment-Test: 05200-06  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                            NITROMETHANE                                       Date: 04/04/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 06:10:52  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE FEMALE                        CONTROL      188 PPM      375 PPM      750 PPM                                   
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 URINARY SYSTEM                                                                                                                     
                                                                                                                                    
   Kidney                                             (50)         (48)         (49)         (50)                                   
      Hepatocholangiocarcinoma, Metastatic, Liver      1 (2%)                                                                       
      Histiocytic Sarcoma                                                        2 (4%)                                             
      Osteosarcoma, Metastatic, Bone                                             1 (2%)                                             
   Urinary Bladder                                    (49)         (47)         (47)         (49)                                   
      Histiocytic Sarcoma                                                        1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SYSTEMIC LESIONS                                                                                                                   

   Multiple Organs                                   *(50)        *(50)        *(50)        *(50)                                   
      Histiocytic Sarcoma                              2 (4%)                    3 (6%)                                             
      Lymphoma Malignant                               9 (18%)      7 (14%)      7 (14%)      7 (14%)                               
____________________________________________________________________________________________________________________________________

                                                                                                                                    
     *   Number of animals with any tissue examined microscopically                                                                 

                                                             Page   6                                                               
NTP Experiment-Test: 05200-06  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                            NITROMETHANE                                       Date: 04/04/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 06:10:52  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE FEMALE                        CONTROL      188 PPM      375 PPM      750 PPM                                   
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
TUMOR SUMMARY                                                                                                                       
                                                                                                                                    
   Total Animals with Primary Neoplasms (b)            38          45          43          46                                       
     Total Primary Neoplasms                           83          95          92         110                                       
                                                                                                                                    
   Total Animals with Benign Neoplasms                 31          39          33          43                                       
     Total Benign Neoplasms                            48          62          50          82                                       
                                                                                                                                    
   Total Animals with Malignant Neoplasms              26          24          28          21                                       
     Total Malignant Neoplasms                         35          33          42          28                                       
                                                                                                                                    
   Total Animals with Metastatic Neoplasms              4           5           3           4                                       
     Total Metastatic Neoplasm                         11          14           5           5                                       
                                                                                                                                    
   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   7                                                               
NTP Experiment-Test: 05200-06  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                            NITROMETHANE                                       Date: 04/04/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 06:10:52  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE MALE                          CONTROL      188 PPM      375 PPM      750 PPM                                   
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
DISPOSITION SUMMARY                                                                                                                 

  Animals Initially in Study                          50           50           50           50                                     
  Early Deaths                                                                                                                      
    Moribund Sacrifice                                14           11           16           16                                     
    Natural Death                                      5            3            4            5                                     
  Survivors                                                                                                                         
    Terminal Sacrifice                                31           36           30           29                                     

  Animals Examined Microscopically                    50           50           50           50                                     
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ALIMENTARY SYSTEM                                                                                                                  
                                                                                                                                    
   Intestine Small, Jejunum                           (45)         (49)         (47)         (46)                                   
   Intestine Small, Ileum                             (46)         (48)         (46)         (45)                                   
   Liver                                              (50)         (50)         (50)         (50)                                   
      Hemangiosarcoma                                  1 (2%)       2 (4%)       2 (4%)                                             
      Hepatocellular Carcinoma                        11 (22%)     12 (24%)      8 (16%)      6 (12%)                               
      Hepatocellular Carcinoma, Multiple               5 (10%)      2 (4%)       2 (4%)       3 (6%)                                
      Hepatocellular Adenoma                          10 (20%)     10 (20%)     12 (24%)     11 (22%)                               
      Hepatocellular Adenoma, Multiple                 7 (14%)      4 (8%)       1 (2%)       6 (12%)                               
      Hepatocholangiocarcinoma, Multiple               1 (2%)                                                                       
      Histiocytic Sarcoma                                                        3 (6%)                                             
      Squamous Cell Carcinoma, Metastatic, Stomach,                                                                                 
           Forestomach                                              1 (2%)                                                          
   Mesentery                                          (3)                       (6)          (2)                                    
      Fat, Histiocytic Sarcoma                                                   2 (33%)                                            
   Pancreas                                           (49)         (50)         (49)         (49)                                   
      Adenoma                                                       1 (2%)                                                          
      Histiocytic Sarcoma                                                        2 (4%)                                             
   Salivary Glands                                    (50)         (49)         (50)         (49)                                   
   Stomach, Forestomach                               (49)         (50)         (50)         (48)                                   
      Histiocytic Sarcoma                                                        1 (2%)                                             
      Squamous Cell Carcinoma                                       1 (2%)                                                          
      Squamous Cell Papilloma                                       1 (2%)                    1 (2%)                                
   Stomach, Glandular                                 (48)         (48)         (48)         (48)                                   
      Histiocytic Sarcoma                                                        1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 CARDIOVASCULAR SYSTEM                                                                                                              
                                                                                                                                    
   Heart                                              (50)         (50)         (50)         (50)                                   
      Hepatocellular Carcinoma, Metastatic, Liver      1 (2%)                                                                       
____________________________________________________________________________________________________________________________________
                                                                                                                                    

                                                             Page   8                                                               
NTP Experiment-Test: 05200-06  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                            NITROMETHANE                                       Date: 04/04/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 06:10:52  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE MALE                          CONTROL      188 PPM      375 PPM      750 PPM                                   
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ENDOCRINE SYSTEM                                                                                                                   
                                                                                                                                    
   Adrenal Cortex                                     (49)         (50)         (49)         (48)                                   
      Adenoma                                                                                 2 (4%)                                
      Bilateral, Capsule, Adenoma                                                1 (2%)                                             
      Capsule, Adenoma                                 5 (10%)      1 (2%)       1 (2%)       3 (6%)                                
   Adrenal Medulla                                    (49)         (50)         (49)         (47)                                   
      Pheochromocytoma Complex                                                   1 (2%)                                             
      Pheochromocytoma Benign                                                                 1 (2%)                                
   Islets, Pancreatic                                 (49)         (50)         (49)         (49)                                   
      Adenoma                                          1 (2%)       3 (6%)                    1 (2%)                                
   Pituitary Gland                                    (47)         (50)         (46)         (47)                                   
      Pars Distalis, Adenoma                           1 (2%)                                                                       
      Pars Intermedia, Adenoma                                                   1 (2%)                                             
   Thyroid Gland                                      (50)         (50)         (49)         (48)                                   
      Follicular Cell, Adenoma                         1 (2%)                                 1 (2%)                                
      Follicular Cell, Carcinoma                                    1 (2%)                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENERAL BODY SYSTEM                                                                                                                
                                                                                                                                    
   None                                                                                                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENITAL SYSTEM                                                                                                                     
                                                                                                                                    
   Epididymis                                         (50)         (50)         (50)         (49)                                   
      Histiocytic Sarcoma                              2 (4%)                                                                       
   Prostate                                           (49)         (50)         (47)         (46)                                   
      Histiocytic Sarcoma                                                        1 (2%)                                             
   Seminal Vesicle                                    (49)         (49)         (49)         (47)                                   
      Histiocytic Sarcoma                                                        1 (2%)                                             
   Testes                                             (50)         (50)         (50)         (50)                                   
      Interstitial Cell, Adenoma                       2 (4%)       1 (2%)       1 (2%)       1 (2%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 HEMATOPOIETIC SYSTEM                                                                                                               
                                                                                                                                    
   Bone Marrow                                        (49)         (50)         (50)         (50)                                   
      Hemangiosarcoma                                  1 (2%)       2 (4%)                                                          
   Lymph Node                                         (3)          (1)          (1)          (2)                                    
   Lymph Node, Bronchial                              (26)         (26)         (24)         (28)                                   
      Histiocytic Sarcoma                                                        1 (4%)                                             
   Lymph Node, Mandibular                             (40)         (39)         (37)         (43)                                   
   Lymph Node, Mesenteric                             (47)         (46)         (47)         (49)                                   
      Histiocytic Sarcoma                                                        2 (4%)       1 (2%)                                
   Lymph Node, Mediastinal                            (35)         (37)         (36)         (40)                                   
      Histiocytic Sarcoma                                                        1 (3%)                                             

                                                             Page   9                                                               
NTP Experiment-Test: 05200-06  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                            NITROMETHANE                                       Date: 04/04/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 06:10:52  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE MALE                          CONTROL      188 PPM      375 PPM      750 PPM                                   
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
HEMATOPOIETIC SYSTEM - cont                                                                                                         
   Spleen                                             (49)         (50)         (50)         (49)                                   
      Hemangiosarcoma                                  1 (2%)       1 (2%)       1 (2%)                                             
      Histiocytic Sarcoma                                                        1 (2%)       1 (2%)                                
   Thymus                                             (33)         (34)         (33)         (40)                                   
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 INTEGUMENTARY SYSTEM                                                                                                               
                                                                                                                                    
   Skin                                               (49)         (49)         (49)         (48)                                   
      Prepuce, Histiocytic Sarcoma                     1 (2%)                                                                       
      Subcutaneous Tissue, Hemangiosarcoma                                       1 (2%)                                             
      Subcutaneous Tissue, Histiocytic Sarcoma         2 (4%)                                                                       
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 MUSCULOSKELETAL SYSTEM                                                                                                             
                                                                                                                                    
   None                                                                                                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 NERVOUS SYSTEM                                                                                                                     
                                                                                                                                    
   Brain                                              (50)         (50)         (50)         (49)                                   
      Carcinoma, Metastatic, Harderian Gland                                     1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 RESPIRATORY SYSTEM                                                                                                                 
                                                                                                                                    
   Lung                                               (50)         (50)         (50)         (50)                                   
      Alveolar/Bronchiolar Adenoma                     9 (18%)     10 (20%)      8 (16%)     11 (22%)                               
      Alveolar/Bronchiolar Adenoma, Multiple           2 (4%)                    1 (2%)       1 (2%)                                
      Alveolar/Bronchiolar Carcinoma                   2 (4%)       3 (6%)       3 (6%)      10 (20%)                               
      Alveolar/Bronchiolar Carcinoma, Multiple                                                1 (2%)                                
      Carcinoma, Metastatic, Harderian Gland                                     1 (2%)       2 (4%)                                
      Hepatocellular Carcinoma, Metastatic, Liver      6 (12%)      1 (2%)       4 (8%)       2 (4%)                                
      Histiocytic Sarcoma                                                        1 (2%)                                             
      Mediastinum, Histiocytic Sarcoma                                           1 (2%)                                             
   Nose                                               (50)         (49)         (50)         (50)                                   
      Carcinoma, Metastatic, Harderian Gland                                     1 (2%)       1 (2%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SPECIAL SENSES SYSTEM                                                                                                              
                                                                                                                                    
   Harderian Gland                                    (49)         (50)         (50)         (49)                                   
      Adenoma                                          9 (18%)      6 (12%)     18 (36%)     25 (51%)                               
      Adenoma, Multiple                                             4 (8%)       1 (2%)       7 (14%)                               
      Carcinoma                                        1 (2%)       1 (2%)       6 (12%)      4 (8%)                                
      Carcinoma, Multiple                                                                     1 (2%)                                

                                                             Page  10                                                               
NTP Experiment-Test: 05200-06  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                            NITROMETHANE                                       Date: 04/04/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 06:10:52  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE MALE                          CONTROL      188 PPM      375 PPM      750 PPM                                   
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
SPECIAL SENSES SYSTEM - cont                                                                                                        
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 URINARY SYSTEM                                                                                                                     
                                                                                                                                    
   Kidney                                             (50)         (50)         (49)         (49)                                   
      Renal Tubule, Adenoma                                                      1 (2%)                                             
   Urinary Bladder                                    (48)         (50)         (49)         (48)                                   
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SYSTEMIC LESIONS                                                                                                                   

   Multiple Organs                                   *(50)        *(50)        *(50)        *(50)                                   
      Histiocytic Sarcoma                              3 (6%)                    3 (6%)       1 (2%)                                
      Lymphoma Malignant                               3 (6%)       4 (8%)       2 (4%)       1 (2%)                                
____________________________________________________________________________________________________________________________________

                                                                                                                                    
     *   Number of animals with any tissue examined microscopically                                                                 

                                                             Page  11                                                               
NTP Experiment-Test: 05200-06  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                            NITROMETHANE                                       Date: 04/04/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 06:10:52  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE MALE                          CONTROL      188 PPM      375 PPM      750 PPM                                   
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
TUMOR SUMMARY                                                                                                                       
                                                                                                                                    
   Total Animals with Primary Neoplasms (b)            40          39          43          46                                       
     Total Primary Neoplasms                           76          70          75          98                                       
                                                                                                                                    
   Total Animals with Benign Neoplasms                 31          31          33          43                                       
     Total Benign Neoplasms                            47          41          46          71                                       
                                                                                                                                    
   Total Animals with Malignant Neoplasms              22          25          24          22                                       
     Total Malignant Neoplasms                         29          29          29          27                                       
                                                                                                                                    
   Total Animals with Metastatic Neoplasms              6           2           5           4                                       
     Total Metastatic Neoplasm                          7           2           7           5                                       
                                                                                                                                    
   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  12                                                               
                             ------------------------------------------------------------                                           
                             ----------              END OF REPORT             ----------                                           
                             ------------------------------------------------------------