National Toxicology Program

National Toxicology Program
https://ntp.niehs.nih.gov/go/18909

TDMS Study 92013-06 Pathology Tables

NTP Experiment-Test: 92013-06  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                         4-METHYLIMIDAZOLE                                     Date: 01/12/04
Route: DOSED FEED                                                                                                 Time: 14:34:49

                                                         FINAL #1 MICE




       Facility:  Southern Research Institute

       Chemical CAS #:  822-36-6

       Lock Date:  09/13/02

       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: 92013-06  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                         4-METHYLIMIDAZOLE                                     Date: 01/12/04  
Route: DOSED FEED                                                                                                 Time: 14:34:49  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE FEMALE                        0 PPM        312 PPM      625 PPM      1250 PPM                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
DISPOSITION SUMMARY                                                                                                                 
                                                                                                                                    
  Animals Initially in Study                          50           50           50           50                                     
  Early Deaths                                                                                                                      
    Moribund Sacrifice                                 3            4            3            3                                     
    Natural Death                                      4            6            4            7                                     
  Survivors                                                                                                                         
    Terminal Sacrifice                                42           40           41           39                                     
    Natural Death                                      1                         2            1                                     
                                                                                                                                    
  Animals Examined Microscopically                    50           50           50           50                                     
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ALIMENTARY SYSTEM                                                                                                                  
                                                                                                                                    
   Intestine Large, Colon                             (48)         (50)         (50)         (49)                                   
      Squamous Cell Carcinoma, Metastatic, Stomach,                                                                                 
           Forestomach                                                           1 (2%)                                             
   Intestine Large, Cecum                             (49)         (48)         (46)         (46)                                   
      Histiocytic Sarcoma                                                                     1 (2%)                                
   Intestine Small, Duodenum                          (48)         (47)         (49)         (48)                                   
      Carcinoma                                                                  2 (4%)                                             
      Histiocytic Sarcoma                                                                     1 (2%)                                
      Polyp Adenomatous                                1 (2%)                                                                       
   Intestine Small, Jejunum                           (50)         (48)         (47)         (47)                                   
   Intestine Small, Ileum                             (48)         (45)         (48)         (48)                                   
   Liver                                              (50)         (50)         (50)         (50)                                   
      Hepatocellular Carcinoma                         1 (2%)       2 (4%)                    1 (2%)                                
      Hepatocellular Adenoma                           4 (8%)       5 (10%)                   1 (2%)                                
      Histiocytic Sarcoma                                           1 (2%)       1 (2%)       2 (4%)                                
      Mast Cell Tumor Malignant                                                               1 (2%)                                
      Sarcoma, Metastatic, Skin                        1 (2%)                                                                       
      Squamous Cell Carcinoma, Metastatic, Stomach,                                                                                 
           Forestomach                                                           1 (2%)                                             
   Mesentery                                          (3)          (7)          (7)          (4)                                    
      Carcinoma, Metastatic, Mammary Gland                          1 (14%)                                                         
      Histiocytic Sarcoma                                           1 (14%)                                                         
      Squamous Cell Carcinoma, Metastatic, Stomach,                                                                                 
           Forestomach                                                           1 (14%)                                            
   Pancreas                                           (49)         (48)         (48)         (49)                                   
      Sarcoma, Metastatic, Skin                        1 (2%)                                                                       
   Salivary Glands                                    (50)         (48)         (50)         (49)                                   
   Stomach, Forestomach                               (50)         (50)         (50)         (50)                                   
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page   2                                                               
                                                                                                                                   
NTP Experiment-Test: 92013-06  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                         4-METHYLIMIDAZOLE                                     Date: 01/12/04  
Route: DOSED FEED                                                                                                 Time: 14:34:49  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE FEMALE                        0 PPM        312 PPM      625 PPM      1250 PPM                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ALIMENTARY SYSTEM - cont                                                                                                            
      Squamous Cell Carcinoma                                                    2 (4%)                                             
      Squamous Cell Papilloma                          2 (4%)                    1 (2%)       2 (4%)                                
   Stomach, Glandular                                 (49)         (49)         (50)         (49)                                   
      Adenoma                                                                                 1 (2%)                                
      Sarcoma, Metastatic, Skin                        1 (2%)                                                                       
      Squamous Cell Carcinoma, Metastatic, Stomach,                                                                                 
           Forestomach                                                           1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 CARDIOVASCULAR SYSTEM                                                                                                              
                                                                                                                                    
   Heart                                              (50)         (50)         (50)         (50)                                   
      Carcinoma, Metastatic, Mammary Gland                          1 (2%)                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ENDOCRINE SYSTEM                                                                                                                   
                                                                                                                                    
   Adrenal Cortex                                     (50)         (50)         (50)         (50)                                   
      Carcinoma, Metastatic, Mammary Gland                          1 (2%)                                                          
      Capsule, Adenoma                                              1 (2%)                                                          
   Adrenal Medulla                                    (50)         (50)         (50)         (50)                                   
      Pheochromocytoma Malignant                       1 (2%)                                 1 (2%)                                
      Pheochromocytoma Benign                                       1 (2%)                                                          
   Islets, Pancreatic                                 (49)         (48)         (47)         (49)                                   
      Adenoma                                                       3 (6%)                                                          
      Carcinoma                                                     1 (2%)       1 (2%)                                             
   Pituitary Gland                                    (49)         (46)         (49)         (50)                                   
      Pars Distalis, Adenoma                           5 (10%)      4 (9%)       3 (6%)       2 (4%)                                
   Thyroid Gland                                      (50)         (49)         (50)         (48)                                   
      Bilateral, Adenoma                               1 (2%)                                                                       
      Follicular Cell, Adenoma                                                   1 (2%)       1 (2%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENERAL BODY SYSTEM                                                                                                                
                                                                                                                                    
   None                                                                                                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page   3                                                               
                                                                                                                                   
NTP Experiment-Test: 92013-06  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                         4-METHYLIMIDAZOLE                                     Date: 01/12/04  
Route: DOSED FEED                                                                                                 Time: 14:34:49  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE FEMALE                        0 PPM        312 PPM      625 PPM      1250 PPM                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENITAL SYSTEM                                                                                                                     
                                                                                                                                    
   Ovary                                              (48)         (49)         (49)         (50)                                   
      Cystadenoma                                      2 (4%)                    1 (2%)       1 (2%)                                
      Granulosa Cell Tumor Benign                      2 (4%)                                                                       
      Hemangiosarcoma                                               1 (2%)                                                          
      Histiocytic Sarcoma                                                        1 (2%)                                             
      Luteoma                                                       1 (2%)       2 (4%)       2 (4%)                                
      Tubulostromal Adenoma                                         1 (2%)                    1 (2%)                                
   Uterus                                             (50)         (50)         (50)         (50)                                   
      Carcinoma                                                     1 (2%)                                                          
      Hemangiosarcoma                                               1 (2%)                    1 (2%)                                
      Histiocytic Sarcoma                              1 (2%)       1 (2%)       2 (4%)       2 (4%)                                
      Leiomyoma                                                                  1 (2%)                                             
      Polyp Stromal                                                 2 (4%)                    2 (4%)                                
      Sarcoma, Metastatic, Skin                        1 (2%)                                                                       
      Sarcoma Stromal                                                            1 (2%)                                             
      Schwannoma Malignant                             1 (2%)                                                                       
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 HEMATOPOIETIC SYSTEM                                                                                                               
                                                                                                                                    
   Bone Marrow                                        (50)         (50)         (50)         (50)                                   
      Hemangiosarcoma                                               1 (2%)                    1 (2%)                                
      Histiocytic Sarcoma                                                                     1 (2%)                                
      Mast Cell Tumor Malignant                                                               1 (2%)                                
   Lymph Node                                         (3)          (9)          (12)         (7)                                    
      Iliac, Histiocytic Sarcoma                                    1 (11%)                                                         
      Mediastinal, Histiocytic Sarcoma                                                        1 (14%)                               
      Pancreatic, Squamous Cell Carcinoma,                                                                                          
          Metastatic, Stomach, Forestomach                                       1 (8%)                                             
   Lymph Node, Mandibular                             (47)         (47)         (48)         (48)                                   
      Histiocytic Sarcoma                                           1 (2%)                                                          
   Lymph Node, Mesenteric                             (49)         (47)         (49)         (50)                                   
      Histiocytic Sarcoma                                                                     1 (2%)                                
      Mast Cell Tumor Malignant                                                               1 (2%)                                
      Sarcoma, Metastatic, Skin                        1 (2%)                                                                       
   Spleen                                             (49)         (49)         (49)         (49)                                   
      Fibrosarcoma, Metastatic, Skin                   1 (2%)                                                                       
      Hemangiosarcoma                                  2 (4%)       2 (4%)                                                          
      Histiocytic Sarcoma                                                        1 (2%)                                             
      Mast Cell Tumor Malignant                                                               1 (2%)                                
   Thymus                                             (49)         (49)         (50)         (48)                                   
____________________________________________________________________________________________________________________________________
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page   4                                                               
                                                                                                                                   
NTP Experiment-Test: 92013-06  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                         4-METHYLIMIDAZOLE                                     Date: 01/12/04  
Route: DOSED FEED                                                                                                 Time: 14:34:49  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE FEMALE                        0 PPM        312 PPM      625 PPM      1250 PPM                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
                                                                                                                                    
 INTEGUMENTARY SYSTEM                                                                                                               
                                                                                                                                    
   Mammary Gland                                      (50)         (50)         (49)         (49)                                   
      Adenoma                                                                                 1 (2%)                                
      Carcinoma                                        1 (2%)       1 (2%)                    1 (2%)                                
   Skin                                               (50)         (50)         (50)         (50)                                   
      Basal Cell Carcinoma                                                       1 (2%)                                             
      Subcutaneous Tissue, Fibrosarcoma                1 (2%)                                 1 (2%)                                
      Subcutaneous Tissue, Hemangiosarcoma             2 (4%)                                 1 (2%)                                
      Subcutaneous Tissue, Melanoma Benign                          1 (2%)                                                          
      Subcutaneous Tissue, Sarcoma, Poorly                                                                                          
          Differentiated                               1 (2%)                                                                       
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 MUSCULOSKELETAL SYSTEM                                                                                                             
                                                                                                                                    
   Bone                                               (50)         (50)         (50)         (50)                                   
      Osteosarcoma                                                                            1 (2%)                                
   Skeletal Muscle                                    (1)          (1)          (2)          (2)                                    
      Sarcoma, Metastatic, Skin                        1 (100%)                                                                     
      Squamous Cell Carcinoma, Metastatic, Stomach,                                                                                 
           Forestomach                                                           2 (100%)                                           
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 NERVOUS SYSTEM                                                                                                                     
                                                                                                                                    
   Brain                                              (50)         (50)         (50)         (50)                                   
      Carcinoma, Metastatic, Mammary Gland                          1 (2%)                                                          
      Histiocytic Sarcoma                                           1 (2%)                                                          
      Mast Cell Tumor Malignant                                                               1 (2%)                                
   Spinal Cord                                                     (2)                       (1)                                    
      Osteosarcoma, Metastatic, Bone                                                          1 (100%)                              
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 RESPIRATORY SYSTEM                                                                                                                 
                                                                                                                                    
   Lung                                               (50)         (50)         (50)         (50)                                   
      Alveolar/Bronchiolar Adenoma                                  8 (16%)     12 (24%)      6 (12%)                               
      Alveolar/Bronchiolar Adenoma, Multiple                                     4 (8%)       2 (4%)                                
      Alveolar/Bronchiolar Carcinoma                   3 (6%)                    2 (4%)       6 (12%)                               
      Alveolar/Bronchiolar Carcinoma, Multiple                                                1 (2%)                                
      Carcinoma, Metastatic, Mammary Gland                          1 (2%)                                                          
      Histiocytic Sarcoma                                                                     2 (4%)                                
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page   5                                                               
                                                                                                                                   
NTP Experiment-Test: 92013-06  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                         4-METHYLIMIDAZOLE                                     Date: 01/12/04  
Route: DOSED FEED                                                                                                 Time: 14:34:49  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE FEMALE                        0 PPM        312 PPM      625 PPM      1250 PPM                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
RESPIRATORY SYSTEM - cont                                                                                                           
      Mast Cell Tumor Malignant                                                               1 (2%)                                
      Osteosarcoma, Metastatic, Bone                                                          1 (2%)                                
      Sarcoma, Metastatic, Skin                        1 (2%)                                                                       
   Nose                                               (50)         (49)         (50)         (50)                                   
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SPECIAL SENSES SYSTEM                                                                                                              
                                                                                                                                    
   Harderian Gland                                    (50)         (50)         (50)         (50)                                   
      Adenoma                                          6 (12%)      1 (2%)       5 (10%)      6 (12%)                               
      Carcinoma                                        1 (2%)       1 (2%)                    2 (4%)                                
   Zymbal's Gland                                     (1)                       (1)                                                 
      Carcinoma                                        1 (100%)                  1 (100%)                                           
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 URINARY SYSTEM                                                                                                                     
                                                                                                                                    
   Kidney                                             (49)         (50)         (50)         (50)                                   
      Carcinoma, Metastatic, Mammary Gland                          1 (2%)                                                          
      Histiocytic Sarcoma                                                        1 (2%)                                             
   Urinary Bladder                                    (50)         (50)         (50)         (50)                                   
      Histiocytic Sarcoma                                           1 (2%)                                                          
      Sarcoma, Metastatic, Skin                        1 (2%)                                                                       
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SYSTEMIC LESIONS                                                                                                                   
                                                                                                                                    
   Multiple Organs                                   *(50)        *(50)        *(50)        *(50)                                   
      Histiocytic Sarcoma                              1 (2%)       1 (2%)       3 (6%)       2 (4%)                                
      Lymphoma Malignant                               7 (14%)     10 (20%)     12 (24%)     13 (26%)                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
     *   Number of animals with any tissue examined microscopically                                                                 
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page   6                                                               
                                                                                                                                   
NTP Experiment-Test: 92013-06  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                         4-METHYLIMIDAZOLE                                     Date: 01/12/04  
Route: DOSED FEED                                                                                                 Time: 14:34:49  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE FEMALE                        0 PPM        312 PPM      625 PPM      1250 PPM                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
TUMOR SUMMARY                                                                                                                       
                                                                                                                                    
   Total Animals with Primary Neoplasms (b)            29          36          37          40                                       
     Total Primary Neoplasms                           46          50          55          66                                       
                                                                                                                                    
   Total Animals with Benign Neoplasms                 18          23          23          21                                       
     Total Benign Neoplasms                            23          28          30          28                                       
                                                                                                                                    
   Total Animals with Malignant Neoplasms              20          20          23          29                                       
     Total Malignant Neoplasms                         23          22          25          38                                       
                                                                                                                                    
   Total Animals with Metastatic Neoplasms              2           1           2           1                                       
     Total Metastatic Neoplasm                          9           6           7           2                                       
                                                                                                                                    
   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: 92013-06  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                         4-METHYLIMIDAZOLE                                     Date: 01/12/04  
Route: DOSED FEED                                                                                                 Time: 14:34:49  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE MALE                          0 PPM        312 PPM      625 PPM      1250 PPM                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
DISPOSITION SUMMARY                                                                                                                 
                                                                                                                                    
  Animals Initially in Study                          50           50           50           50                                     
  Early Deaths                                                                                                                      
    Natural Death                                      4            6            8                                                  
    Moribund Sacrifice                                 1                                      3                                     
  Survivors                                                                                                                         
    Natural Death                                      1                                                                            
    Terminal Sacrifice                                44           44           42           46                                     
  Other                                                                                       1                                     
                                                                                                                                    
  Animals Examined Microscopically                    50           50           50           50                                     
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ALIMENTARY SYSTEM                                                                                                                  
                                                                                                                                    
   Intestine Small, Duodenum                          (50)         (49)         (48)         (50)                                   
      Carcinoma                                                     2 (4%)                                                          
      Polyp Adenomatous                                             1 (2%)                                                          
   Intestine Small, Jejunum                           (48)         (47)         (48)         (50)                                   
      Carcinoma                                                     1 (2%)                                                          
   Intestine Small, Ileum                             (49)         (46)         (48)         (49)                                   
   Liver                                              (50)         (50)         (50)         (50)                                   
      Hemangiosarcoma                                                            1 (2%)       1 (2%)                                
      Hemangiosarcoma, Multiple                                                  1 (2%)                                             
      Hepatocellular Carcinoma                         8 (16%)     11 (22%)     10 (20%)      7 (14%)                               
      Hepatocellular Carcinoma, Multiple               2 (4%)       2 (4%)       1 (2%)       3 (6%)                                
      Hepatocellular Adenoma                          14 (28%)      7 (14%)     10 (20%)     11 (22%)                               
      Hepatocellular Adenoma, Multiple                 3 (6%)       2 (4%)       1 (2%)                                             
   Mesentery                                          (4)          (7)          (2)          (3)                                    
      Hemangiosarcoma                                               1 (14%)                   1 (33%)                               
      Hepatocellular Carcinoma, Metastatic, Liver                   1 (14%)                                                         
      Sarcoma, Poorly Differentiated                                1 (14%)                                                         
   Oral Mucosa                                                                  (1)                                                 
      Squamous Cell Carcinoma                                                    1 (100%)                                           
   Pancreas                                           (49)         (49)         (50)         (50)                                   
      Sarcoma, Metastatic, Mesentery                                1 (2%)                                                          
   Salivary Glands                                    (50)         (50)         (50)         (50)                                   
   Stomach, Forestomach                               (49)         (50)         (50)         (50)                                   
      Squamous Cell Carcinoma                          1 (2%)                                                                       
      Squamous Cell Papilloma                                       2 (4%)                    3 (6%)                                
   Stomach, Glandular                                 (49)         (50)         (49)         (50)                                   
      Hepatocellular Carcinoma, Metastatic, Liver                                1 (2%)                                             
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page   8                                                               
                                                                                                                                   
NTP Experiment-Test: 92013-06  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                         4-METHYLIMIDAZOLE                                     Date: 01/12/04  
Route: DOSED FEED                                                                                                 Time: 14:34:49  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE MALE                          0 PPM        312 PPM      625 PPM      1250 PPM                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 CARDIOVASCULAR SYSTEM                                                                                                              
                                                                                                                                    
   Heart                                              (50)         (50)         (50)         (50)                                   
      Hemangiosarcoma                                                            1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ENDOCRINE SYSTEM                                                                                                                   
                                                                                                                                    
   Adrenal Cortex                                     (50)         (50)         (50)         (50)                                   
      Adenoma                                          1 (2%)                                                                       
      Capsule, Adenoma                                 3 (6%)       1 (2%)       1 (2%)                                             
      Capsule, Carcinoma                                            1 (2%)                                                          
   Islets, Pancreatic                                 (49)         (49)         (50)         (50)                                   
      Adenoma                                                       1 (2%)                    1 (2%)                                
   Pituitary Gland                                    (49)         (48)         (49)         (50)                                   
      Pars Distalis, Adenoma                                        1 (2%)                                                          
   Thyroid Gland                                      (50)         (50)         (50)         (50)                                   
      Follicular Cell, Adenoma                         1 (2%)       1 (2%)                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENERAL BODY SYSTEM                                                                                                                
                                                                                                                                    
   Tissue NOS                                         (1)                                                                           
      Schwannoma Malignant                             1 (100%)                                                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENITAL SYSTEM                                                                                                                     
                                                                                                                                    
   Prostate                                           (50)         (50)         (50)         (50)                                   
      Carcinoma                                                                  1 (2%)                                             
   Testes                                             (50)         (50)         (50)         (50)                                   
      Hemangiosarcoma                                                            1 (2%)       1 (2%)                                
      Interstitial Cell, Adenoma                                    2 (4%)                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 HEMATOPOIETIC SYSTEM                                                                                                               
                                                                                                                                    
   Bone Marrow                                        (50)         (50)         (50)         (50)                                   
      Hemangiosarcoma                                  1 (2%)       1 (2%)                                                          
   Lymph Node                                         (2)          (2)          (1)          (2)                                    
   Lymph Node, Mandibular                             (48)         (50)         (48)         (45)                                   
   Lymph Node, Mesenteric                             (49)         (48)         (48)         (50)                                   
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page   9                                                               
                                                                                                                                   
NTP Experiment-Test: 92013-06  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                         4-METHYLIMIDAZOLE                                     Date: 01/12/04  
Route: DOSED FEED                                                                                                 Time: 14:34:49  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE MALE                          0 PPM        312 PPM      625 PPM      1250 PPM                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
HEMATOPOIETIC SYSTEM - cont                                                                                                         
   Spleen                                             (49)         (49)         (50)         (50)                                   
      Hemangiosarcoma                                               1 (2%)                    1 (2%)                                
   Thymus                                             (48)         (49)         (45)         (45)                                   
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 INTEGUMENTARY SYSTEM                                                                                                               
                                                                                                                                    
   Skin                                               (50)         (50)         (50)         (49)                                   
      Squamous Cell Carcinoma                                       1 (2%)                                                          
      Sebaceous Gland, Adenoma                                                                1 (2%)                                
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 MUSCULOSKELETAL SYSTEM                                                                                                             
                                                                                                                                    
   Skeletal Muscle                                    (1)          (2)          (1)          (1)                                    
      Carcinoma, Metastatic, Prostate                                            1 (100%)                                           
      Hemangiosarcoma                                  1 (100%)                                                                     
      Sarcoma, Metastatic, Mesentery                                1 (50%)                                                         
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 NERVOUS SYSTEM                                                                                                                     
                                                                                                                                    
   None                                                                                                                             
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 RESPIRATORY SYSTEM                                                                                                                 
                                                                                                                                    
   Lung                                               (50)         (50)         (50)         (50)                                   
      Alveolar/Bronchiolar Adenoma                     6 (12%)     10 (20%)     10 (20%)     14 (28%)                               
      Alveolar/Bronchiolar Adenoma, Multiple           2 (4%)       1 (2%)       3 (6%)       1 (2%)                                
      Alveolar/Bronchiolar Carcinoma                   2 (4%)       3 (6%)       4 (8%)       7 (14%)                               
      Alveolar/Bronchiolar Carcinoma, Multiple                      1 (2%)                    1 (2%)                                
      Carcinoma, Metastatic, Prostate                                            1 (2%)                                             
      Hepatocellular Carcinoma, Metastatic, Liver      3 (6%)       3 (6%)       3 (6%)       3 (6%)                                
      Schwannoma Malignant, Metastatic, Tissue NOS     1 (2%)                                                                       
      Mediastinum, Hemangiosarcoma                     1 (2%)                                                                       
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                                                             Page  10                                                               
                                                                                                                                   
NTP Experiment-Test: 92013-06  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                         4-METHYLIMIDAZOLE                                     Date: 01/12/04  
Route: DOSED FEED                                                                                                 Time: 14:34:49  
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         B6C3F1 MICE MALE                          0 PPM        312 PPM      625 PPM      1250 PPM                                  
                                                                                                                                    
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 SPECIAL SENSES SYSTEM                                                                                                              
                                                                                                                                    
   Harderian Gland                                    (50)         (50)         (50)         (50)                                   
      Adenoma                                          3 (6%)       8 (16%)      4 (8%)       6 (12%)                               
      Adenoma, Multiple                                1 (2%)                                 1 (2%)                                
      Carcinoma                                        1 (2%)                                 1 (2%)                                
      Bilateral, Adenoma                                            1 (2%)                                                          
      Bilateral, Carcinoma                                          1 (2%)                                                          
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 URINARY SYSTEM                                                                                                                     
                                                                                                                                    
   Kidney                                             (50)         (50)         (50)         (50)                                   
      Hepatocellular Carcinoma, Metastatic, Liver      1 (2%)                                                                       
      Renal Tubule, Adenoma                                                      2 (4%)                                             
      Renal Tubule, Carcinoma                                                    1 (2%)                                             
                                                                                                                                    
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 SYSTEMIC LESIONS                                                                                                                   
                                                                                                                                    
   Multiple Organs                                   *(50)        *(50)        *(50)        *(50)                                   
      Lymphoma Malignant                               3 (6%)       3 (6%)       4 (8%)       2 (4%)                                
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     *   Number of animals with any tissue examined microscopically                                                                 
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  11                                                               
                                                                                                                                   
NTP Experiment-Test: 92013-06  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                         4-METHYLIMIDAZOLE                                     Date: 01/12/04  
Route: DOSED FEED                                                                                                 Time: 14:34:49  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         B6C3F1 MICE MALE                          0 PPM        312 PPM      625 PPM      1250 PPM                                  
                                                                                                                                    
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TUMOR SUMMARY                                                                                                                       
                                                                                                                                    
   Total Animals with Primary Neoplasms (b)            34          38          36          39                                       
     Total Primary Neoplasms                           55          68          57          63                                       
                                                                                                                                    
   Total Animals with Benign Neoplasms                 26          29          23          27                                       
     Total Benign Neoplasms                            34          38          31          38                                       
                                                                                                                                    
   Total Animals with Malignant Neoplasms              15          25          21          22                                       
     Total Malignant Neoplasms                         21          30          26          25                                       
                                                                                                                                    
   Total Animals with Metastatic Neoplasms              4           3           4           3                                       
     Total Metastatic Neoplasm                          5           6           6           3                                       
                                                                                                                                    
   Total Animals with Malignant Neoplasms                                                                                           
   Uncertain Primary Site                                                                                                           
                                                                                                                                    
   Total Animals with Neoplasms Uncertain-                                                                                          
   Benign or Malignant                                                                                                              
     Total Uncertain Neoplasms                                                                                                      
                                                                                                                                    
                                                                                                                                    
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a  Number of animals examined microscopically at site and number of animals with lesion                                             
b  Primary tumors: all tumors except metastatic tumors                                                                              
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                             Page  12                                                               
                                                                                                                                   
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                             ----------              END OF REPORT             ----------                                           
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NTP is located at the National Institute of Environmental Health Sciences, part of the National Institutes of Health.