National Toxicology Program

National Toxicology Program
https://ntp.niehs.nih.gov/go/2980

TDMS Study 05136-07 Pathology Tables

NTP Experiment-Test: 05136-07  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                            CHLOROPRENE                                        Date: 09/13/96
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 15:36:30

                                                           CORE STUDY




       Facility:  Battelle Northwest

       Chemical CAS #:  0000126-99-8

       Lock Date:  05/04/94

       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: 05136-07  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                            CHLOROPRENE                                        Date: 09/13/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 15:36:30  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS FEMALE                   CONTROL      12.8 PPM     32 PPM       80 PPM                                    
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
DISPOSITION SUMMARY                                                                                                                 
  Animals Initially in Study                          50           50           50           50                                     
  Early Deaths                                                                                                                      
    Moribund Sacrifice                                19           21           23           27                                     
    Natural Death                                      1            1            1            2                                     
  Survivors                                                                                                                         
    Terminal Sacrifice                                29           28           26           21                                     
  Other                                                1                                                                            
  Animals Examined Microscopically                    49           50           50           50                                     
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ALIMENTARY SYSTEM                                                                                                                  
                                                                                                                                    
   Esophagus                                          (49)         (50)         (50)         (50)                                   
      Squamous Cell Papilloma                                                                 1 (2%)                                
   Intestine Large, Colon                             (49)         (49)         (50)         (49)                                   
   Intestine Large, Cecum                             (48)         (49)         (50)         (49)                                   
   Intestine Small, Duodenum                          (49)         (49)         (50)         (50)                                   
   Intestine Small, Jejunum                           (49)         (49)         (49)         (48)                                   
   Intestine Small, Ileum                             (48)         (49)         (49)         (48)                                   
   Liver                                              (49)         (50)         (50)         (50)                                   
      Hemangiosarcoma                                                                         1 (2%)                                
      Histiocytic Sarcoma                                                                     1 (2%)                                
   Mesentery                                          (5)          (6)          (8)          (11)                                   
      Lipoma                                                                     1 (13%)                                            
   Oral Mucosa                                        (1)          (1)          (2)          (1)                                    
      Buccal, Squamous Cell Papilloma                                                         1 (100%)                              
      Gingival, Squamous Cell Papilloma                                          1 (50%)                                            
      Pharyngeal, Squamous Cell Carcinoma                                        1 (50%)                                            
      Pharyngeal, Squamous Cell Papilloma              1 (100%)     1 (100%)                                                        
   Pancreas                                           (49)         (50)         (50)         (50)                                   
   Salivary Glands                                    (49)         (50)         (50)         (50)                                   
   Stomach, Forestomach                               (49)         (50)         (50)         (50)                                   
   Stomach, Glandular                                 (49)         (50)         (50)         (50)                                   
   Tongue                                             (1)          (4)          (5)          (12)                                   
      Squamous Cell Carcinoma                                       1 (25%)      2 (40%)      4 (33%)                               
      Squamous Cell Papilloma                                       2 (50%)      1 (20%)      6 (50%)                               
      Squamous Cell Papilloma, Multiple                                                       1 (8%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
                                                             Page   2                                                               
NTP Experiment-Test: 05136-07  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                            CHLOROPRENE                                        Date: 09/13/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 15:36:30  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS FEMALE                   CONTROL      12.8 PPM     32 PPM       80 PPM                                    
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 CARDIOVASCULAR SYSTEM                                                                                                              
                                                                                                                                    
   Heart                                              (49)         (50)         (50)         (50)                                   
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ENDOCRINE SYSTEM                                                                                                                   
                                                                                                                                    
   Adrenal Cortex                                     (49)         (50)         (50)         (50)                                   
      Adenoma                                          2 (4%)       4 (8%)       2 (4%)       1 (2%)                                
   Adrenal Medulla                                    (49)         (50)         (50)         (50)                                   
      Pheochromocytoma Complex                                      1 (2%)                                                          
      Pheochromocytoma Benign                          3 (6%)       3 (6%)       3 (6%)       2 (4%)                                
      Bilateral, Pheochromocytoma Benign                                                      1 (2%)                                
   Islets, Pancreatic                                 (49)         (50)         (50)         (50)                                   
      Adenoma                                          2 (4%)       1 (2%)       1 (2%)                                             
      Carcinoma                                        1 (2%)       1 (2%)       1 (2%)                                             
   Pituitary Gland                                    (48)         (50)         (50)         (50)                                   
      Pars Distalis, Adenoma                          36 (75%)     44 (88%)     44 (88%)     36 (72%)                               
   Thyroid Gland                                      (49)         (50)         (50)         (50)                                   
      Bilateral, C-Cell, Adenoma                                    1 (2%)                                                          
      C-Cell, Adenoma                                  7 (14%)      2 (4%)       5 (10%)      5 (10%)                               
      C-Cell, Carcinoma                                1 (2%)       2 (4%)       1 (2%)                                             
      Follicular Cell, Adenoma                         1 (2%)       1 (2%)                    3 (6%)                                
      Follicular Cell, Carcinoma                                                 1 (2%)       2 (4%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENERAL BODY SYSTEM                                                                                                                
                                                                                                                                    
   None                                                                                                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENITAL SYSTEM                                                                                                                     
                                                                                                                                    
   Clitoral Gland                                     (46)         (48)         (46)         (46)                                   
      Adenoma                                          2 (4%)       5 (10%)      2 (4%)       2 (4%)                                
      Carcinoma                                                     5 (10%)      4 (9%)       2 (4%)                                
      Bilateral, Adenoma                                            1 (2%)                                                          
      Bilateral, Carcinoma                                          1 (2%)                                                          
   Ovary                                              (49)         (50)         (50)         (50)                                   
   Uterus                                             (49)         (50)         (50)         (50)                                   
      Deciduoma Malignant                                                        1 (2%)                                             
      Granular Cell Tumor Malignant                    1 (2%)                                                                       
      Leiomyosarcoma                                   1 (2%)                                                                       
      Polyp Stromal                                    6 (12%)      4 (8%)       5 (10%)      8 (16%)                               
      Polyp Stromal, Multiple                                                    1 (2%)       2 (4%)                                
      Schwannoma Malignant                             1 (2%)                                                                       
   Vagina                                             (1)                                                                           
      Schwannoma Malignant, Metastatic, Uterus         1 (100%)                                                                     
                                                             Page   3                                                               
NTP Experiment-Test: 05136-07  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                            CHLOROPRENE                                        Date: 09/13/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 15:36:30  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS FEMALE                   CONTROL      12.8 PPM     32 PPM       80 PPM                                    
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 HEMATOPOIETIC SYSTEM                                                                                                               
                                                                                                                                    
   Bone Marrow                                        (49)         (50)         (50)         (50)                                   
   Lymph Node                                         (1)          (4)          (4)          (5)                                    
   Lymph Node, Bronchial                              (35)         (34)         (30)         (36)                                   
   Lymph Node, Mandibular                             (44)         (48)         (37)         (50)                                   
   Lymph Node, Mesenteric                             (49)         (50)         (49)         (49)                                   
   Lymph Node, Mediastinal                            (44)         (43)         (43)         (45)                                   
   Spleen                                             (48)         (50)         (50)         (50)                                   
      Histiocytic Sarcoma                                                                     1 (2%)                                
   Thymus                                             (43)         (41)         (48)         (46)                                   
      Thymoma Malignant                                                          1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 INTEGUMENTARY SYSTEM                                                                                                               
                                                                                                                                    
   Mammary Gland                                      (49)         (50)         (50)         (50)                                   
      Carcinoma                                        4 (8%)       5 (10%)      4 (8%)       4 (8%)                                
      Fibroadenoma                                    19 (39%)     20 (40%)     21 (42%)     17 (34%)                               
      Fibroadenoma, Multiple                           5 (10%)     12 (24%)     15 (30%)     19 (38%)                               
   Skin                                               (49)         (50)         (50)         (50)                                   
      Basal Cell Carcinoma                                                       1 (2%)                                             
      Keratoacanthoma                                                                         1 (2%)                                
      Subcutaneous Tissue, Fibroma                                               1 (2%)                                             
      Subcutaneous Tissue, Fibrosarcoma                2 (4%)                    1 (2%)                                             
      Subcutaneous Tissue, Lipoma                                                             1 (2%)                                
      Subcutaneous Tissue, Melanoma Malignant          1 (2%)                    1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 MUSCULOSKELETAL SYSTEM                                                                                                             
                                                                                                                                    
   Bone                                               (49)         (50)         (50)         (50)                                   
      Chordoma                                                                   1 (2%)                                             
      Hemangiosarcoma                                                                         1 (2%)                                
      Osteosarcoma                                     1 (2%)                                                                       
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 NERVOUS SYSTEM                                                                                                                     
                                                                                                                                    
   Brain                                              (49)         (50)         (50)         (50)                                   
      Astrocytoma Benign                               1 (2%)                                                                       
      Glioma Benign                                                 1 (2%)                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
                                                             Page   4                                                               
NTP Experiment-Test: 05136-07  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                            CHLOROPRENE                                        Date: 09/13/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 15:36:30  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS FEMALE                   CONTROL      12.8 PPM     32 PPM       80 PPM                                    
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 RESPIRATORY SYSTEM                                                                                                                 
                                                                                                                                    
   Lung                                               (49)         (50)         (50)         (50)                                   
      Alveolar/Bronchiolar Adenoma                     1 (2%)                                 2 (4%)                                
      Alveolar/Bronchiolar Adenoma, Multiple                                                  1 (2%)                                
      Carcinoma, Metastatic, Thyroid Gland                                       1 (2%)                                             
      Chordoma, Metastatic, Bone                                                 1 (2%)                                             
      Hemangiosarcoma, Metastatic, Liver                                                      1 (2%)                                
   Nose                                               (49)         (50)         (50)         (50)                                   
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SPECIAL SENSES SYSTEM                                                                                                              
                                                                                                                                    
   None                                                                                                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 URINARY SYSTEM                                                                                                                     
                                                                                                                                    
   Kidney                                             (49)         (50)         (50)         (50)                                   
      Mesenchymal Tumor NOS                                                                   1 (2%)                                
      Renal Tubule, Adenoma                                                                   2 (4%)                                
      Transitional Epithelium, Carcinoma                            1 (2%)                                                          
   Urinary Bladder                                    (49)         (50)         (50)         (50)                                   
      Leiomyosarcoma                                                             1 (2%)                                             
      Schwannoma Malignant, Metastatic, Uterus         1 (2%)                                                                       
      Transitional Epithelium, Carcinoma                                                      2 (4%)                                
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SYSTEMIC LESIONS                                                                                                                   
   Multiple Organs                                   *(49)        *(50)        *(50)        *(50)                                   
      Histiocytic Sarcoma                                                                     1 (2%)                                
      Leukemia Mononuclear                            18 (37%)     18 (36%)     20 (40%)     26 (52%)                               
      Mesothelioma Benign                              1 (2%)                                                                       
      Mesothelioma NOS                                 1 (2%)                                                                       
____________________________________________________________________________________________________________________________________
                                                                                                                                    
     *   Number of animals with any tissue examined microscopically                                                                 
                                                             Page   5                                                               
NTP Experiment-Test: 05136-07  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                            CHLOROPRENE                                        Date: 09/13/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 15:36:30  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS FEMALE                   CONTROL      12.8 PPM     32 PPM       80 PPM                                    
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
TUMOR SUMMARY                                                                                                                       
                                                                                                                                    
   Total Animals with Primary Neoplasms (b)            47          50          50          49                                       
     Total Primary Neoplasms                          119         137         144         156                                       
                                                                                                                                    
   Total Animals with Benign Neoplasms                 44          48          49          46                                       
     Total Benign Neoplasms                            87         102         103         112                                       
                                                                                                                                    
   Total Animals with Malignant Neoplasms              26          26          31          37                                       
     Total Malignant Neoplasms                         31          35          41          43                                       
                                                                                                                                    
   Total Animals with Metastatic Neoplasms              1                       2           1                                       
     Total Metastatic Neoplasm                          2                       2           1                                       
                                                                                                                                    
   Total Animals with Malignant Neoplasms                                                                                           
   Uncertain Primary Site                                                                                                           
                                                                                                                                    
   Total Animals with Neoplasms Uncertain-                                                                                          
   Benign or Malignant                                  1                                   1                                       
     Total Uncertain Neoplasms                          1                                   1                                       
                                                                                                                                    
____________________________________________________________________________________________________________________________________
a  Number of animals examined microscopically at site and number of animals with lesion                                             
b  Primary tumors: all tumors except metastatic tumors                                                                              
                                                             Page   6                                                               
NTP Experiment-Test: 05136-07  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                            CHLOROPRENE                                        Date: 09/13/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 15:36:30  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS MALE                     CONTROL      12.8 PPM     32 PPM       80 PPM                                    
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
DISPOSITION SUMMARY                                                                                                                 
  Animals Initially in Study                          50           50           50           50                                     
  Early Deaths                                                                                                                      
    Moribund Sacrifice                                34           40           41           41                                     
    Natural Death                                      3            1            4            5                                     
  Survivors                                                                                                                         
    Terminal Sacrifice                                13            9            5            4                                     
  Animals Examined Microscopically                    50           50           50           50                                     
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ALIMENTARY SYSTEM                                                                                                                  
                                                                                                                                    
   Intestine Large, Colon                             (50)         (49)         (48)         (49)                                   
   Intestine Large, Cecum                             (48)         (49)         (46)         (48)                                   
      Polyp Adenomatous                                                                       1 (2%)                                
   Intestine Small, Duodenum                          (50)         (49)         (49)         (50)                                   
      Polyp Adenomatous                                1 (2%)       1 (2%)                                                          
   Intestine Small, Jejunum                           (48)         (49)         (46)         (47)                                   
      Carcinoma                                                                               1 (2%)                                
   Intestine Small, Ileum                             (49)         (49)         (46)         (46)                                   
   Liver                                              (50)         (50)         (49)         (50)                                   
      Histiocytic Sarcoma                                                                     2 (4%)                                
      Schwannoma Malignant, Metastatic, Heart                                    1 (2%)                                             
   Mesentery                                          (16)         (13)         (18)         (13)                                   
      Hemangioma                                                    1 (8%)                                                          
      Sarcoma                                                                    1 (6%)                                             
      Schwannoma Malignant                                                       1 (6%)                                             
      Fat, Lipoma                                                                             1 (8%)                                
   Oral Mucosa                                                     (2)          (1)          (7)                                    
      Buccal, Squamous Cell Papilloma                                                         1 (14%)                               
      Gingival, Squamous Cell Papilloma                                                       1 (14%)                               
      Pharyngeal, Squamous Cell Papilloma                           2 (100%)     1 (100%)     2 (29%)                               
   Pancreas                                           (50)         (50)         (49)         (50)                                   
      Adenoma                                          1 (2%)                    1 (2%)       1 (2%)                                
      Histiocytic Sarcoma                                                                     1 (2%)                                
   Salivary Glands                                    (50)         (50)         (50)         (50)                                   
   Stomach, Forestomach                               (50)         (50)         (50)         (50)                                   
      Histiocytic Sarcoma                                                                     1 (2%)                                
   Stomach, Glandular                                 (49)         (50)         (49)         (50)                                   
      Histiocytic Sarcoma                                                                     1 (2%)                                
   Tongue                                                                       (4)          (8)                                    
      Squamous Cell Carcinoma                                                    1 (25%)      2 (25%)                               
      Squamous Cell Papilloma                                                    3 (75%)      6 (75%)                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
                                                             Page   7                                                               
NTP Experiment-Test: 05136-07  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                            CHLOROPRENE                                        Date: 09/13/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 15:36:30  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS MALE                     CONTROL      12.8 PPM     32 PPM       80 PPM                                    
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 CARDIOVASCULAR SYSTEM                                                                                                              
                                                                                                                                    
   Blood Vessel                                                                 (3)          (1)                                    
      Aorta, Schwannoma Malignant, Metastatic,                                                                                      
           Heart                                                                 1 (33%)                                            
   Heart                                              (50)         (50)         (50)         (50)                                   
      Schwannoma Malignant                                          1 (2%)       1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ENDOCRINE SYSTEM                                                                                                                   
                                                                                                                                    
   Adrenal Cortex                                     (50)         (50)         (49)         (50)                                   
      Adenoma                                          2 (4%)                    1 (2%)                                             
   Adrenal Medulla                                    (50)         (50)         (49)         (50)                                   
      Pheochromocytoma Malignant                       1 (2%)       1 (2%)                                                          
      Pheochromocytoma Benign                         14 (28%)     13 (26%)     11 (22%)      9 (18%)                               
      Bilateral, Pheochromocytoma Benign               5 (10%)      7 (14%)     10 (20%)      9 (18%)                               
   Islets, Pancreatic                                 (50)         (50)         (49)         (50)                                   
      Adenoma                                          3 (6%)       3 (6%)       2 (4%)       2 (4%)                                
      Carcinoma                                        3 (6%)       5 (10%)      3 (6%)       1 (2%)                                
   Parathyroid Gland                                  (48)         (49)         (50)         (50)                                   
      Adenoma                                          1 (2%)                                                                       
   Pituitary Gland                                    (50)         (49)         (50)         (49)                                   
      Pars Distalis, Adenoma                          40 (80%)     40 (82%)     43 (86%)     39 (80%)                               
      Pars Intermedia, Adenoma                                                                1 (2%)                                
   Thyroid Gland                                      (50)         (50)         (49)         (50)                                   
      C-Cell, Adenoma                                  3 (6%)       6 (12%)      4 (8%)       7 (14%)                               
      C-Cell, Carcinoma                                2 (4%)       2 (4%)       2 (4%)                                             
      Follicular Cell, Adenoma                                      2 (4%)       2 (4%)       4 (8%)                                
      Follicular Cell, Carcinoma                                                 2 (4%)       1 (2%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENERAL BODY SYSTEM                                                                                                                
                                                                                                                                    
   Peritoneum                                                                   (3)                                                 
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENITAL SYSTEM                                                                                                                     
                                                                                                                                    
   Epididymis                                         (50)         (50)         (50)         (50)                                   
   Preputial Gland                                    (50)         (50)         (48)         (50)                                   
      Adenoma                                          3 (6%)       3 (6%)       4 (8%)       1 (2%)                                
      Carcinoma                                        3 (6%)       3 (6%)       4 (8%)       1 (2%)                                
      Histiocytic Sarcoma                                                                     1 (2%)                                
   Prostate                                           (50)         (50)         (50)         (50)                                   
      Adenoma                                                       1 (2%)       3 (6%)       1 (2%)                                
   Seminal Vesicle                                    (50)         (50)         (50)         (49)                                   
      Histiocytic Sarcoma                                                                     1 (2%)                                
                                                             Page   8                                                               
NTP Experiment-Test: 05136-07  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                            CHLOROPRENE                                        Date: 09/13/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 15:36:30  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS MALE                     CONTROL      12.8 PPM     32 PPM       80 PPM                                    
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
GENITAL SYSTEM - cont                                                                                                               
   Testes                                             (50)         (50)         (50)         (50)                                   
      Bilateral, Interstitial Cell, Adenoma           23 (46%)     21 (42%)     15 (30%)     17 (34%)                               
      Interstitial Cell, Adenoma                      11 (22%)     13 (26%)     13 (26%)     12 (24%)                               
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 HEMATOPOIETIC SYSTEM                                                                                                               
                                                                                                                                    
   Bone Marrow                                        (50)         (50)         (50)         (50)                                   
      Histiocytic Sarcoma                                                                     1 (2%)                                
   Lymph Node                                         (12)         (18)         (11)         (15)                                   
      Iliac, Histiocytic Sarcoma                                                              1 (7%)                                
   Lymph Node, Bronchial                              (45)         (31)         (44)         (43)                                   
      Alveolar/Bronchiolar Carcinoma, Metastatic,                                                                                   
           Lung                                                                  1 (2%)                                             
      Histiocytic Sarcoma                                                                     2 (5%)                                
   Lymph Node, Mandibular                             (47)         (45)         (44)         (49)                                   
   Lymph Node, Mesenteric                             (50)         (50)         (48)         (50)                                   
      Histiocytic Sarcoma                                                                     1 (2%)                                
   Lymph Node, Mediastinal                            (46)         (47)         (48)         (47)                                   
      Alveolar/Bronchiolar Carcinoma, Metastatic,                                                                                   
           Lung                                                                  1 (2%)                                             
      Histiocytic Sarcoma                                                                     2 (4%)                                
   Spleen                                             (50)         (50)         (49)         (50)                                   
      Hemangiosarcoma                                                            1 (2%)                                             
      Histiocytic Sarcoma                                                                     1 (2%)                                
      Sarcoma                                          1 (2%)       1 (2%)                                                          
   Thymus                                             (42)         (42)         (46)         (48)                                   
      Histiocytic Sarcoma                                                                     1 (2%)                                
      Thymoma Benign                                   1 (2%)                                 2 (4%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 INTEGUMENTARY SYSTEM                                                                                                               
                                                                                                                                    
   Mammary Gland                                      (30)         (23)         (30)         (28)                                   
      Adenoma                                                                    1 (3%)                                             
      Carcinoma                                                     1 (4%)       1 (3%)                                             
      Fibroadenoma                                     2 (7%)       1 (4%)                    1 (4%)                                
   Skin                                               (50)         (50)         (50)         (50)                                   
      Basal Cell Adenoma                               1 (2%)                                                                       
      Basal Cell Carcinoma                                          2 (4%)                                                          
      Histiocytic Sarcoma                                                                     1 (2%)                                
      Keratoacanthoma                                  2 (4%)       4 (8%)       2 (4%)       4 (8%)                                
      Squamous Cell Papilloma                                                    1 (2%)       1 (2%)                                
      Sebaceous Gland, Adenoma                         1 (2%)       2 (4%)                                                          
      Subcutaneous Tissue, Fibroma                                  2 (4%)                    1 (2%)                                
      Subcutaneous Tissue, Fibrosarcoma                1 (2%)                                                                       
      Subcutaneous Tissue, Lipoma                      2 (4%)                                                                       
                                                             Page   9                                                               
NTP Experiment-Test: 05136-07  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                            CHLOROPRENE                                        Date: 09/13/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 15:36:30  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS MALE                     CONTROL      12.8 PPM     32 PPM       80 PPM                                    
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
INTEGUMENTARY SYSTEM - cont                                                                                                         
      Subcutaneous Tissue, Melanoma Malignant                       1 (2%)       1 (2%)                                             
      Subcutaneous Tissue, Sarcoma                     1 (2%)                    1 (2%)       1 (2%)                                
      Subcutaneous Tissue, Schwannoma Malignant                     1 (2%)                                                          
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 MUSCULOSKELETAL SYSTEM                                                                                                             
                                                                                                                                    
   Bone                                               (50)         (50)         (50)         (50)                                   
      Osteosarcoma                                     1 (2%)                                 1 (2%)                                
   Skeletal Muscle                                                 (1)                                                              
      Sarcoma                                                       1 (100%)                                                        
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 NERVOUS SYSTEM                                                                                                                     
                                                                                                                                    
   Brain                                              (50)         (50)         (50)         (50)                                   
      Glioma Malignant, Mixed Cell                                                            1 (2%)                                
      Glioma Malignant, Mixed                          1 (2%)                                                                       
      Meninges, Granular Cell Tumor Benign                                                    1 (2%)                                
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 RESPIRATORY SYSTEM                                                                                                                 
                                                                                                                                    
   Lung                                               (50)         (50)         (49)         (50)                                   
      Alveolar/Bronchiolar Adenoma                     2 (4%)                    3 (6%)       3 (6%)                                
      Alveolar/Bronchiolar Carcinoma                                2 (4%)       1 (2%)       3 (6%)                                
      Alveolar/Bronchiolar Carcinoma, Multiple                                                1 (2%)                                
      Histiocytic Sarcoma                                                                     2 (4%)                                
      Melanoma Malignant, Metastatic, Skin                          1 (2%)                                                          
      Osteosarcoma, Metastatic, Bone                                                          1 (2%)                                
      Mediastinum, Alveolar/Bronchiolar Carcinoma,                                                                                  
           Metastatic, Lung                                                                   1 (2%)                                
      Mediastinum, Schwannoma Malignant,                                                                                            
          Metastatic, Heart                                                      1 (2%)                                             
   Nose                                               (50)         (50)         (49)         (49)                                   
      Respiratory Epithelium, Adenoma                                                         1 (2%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SPECIAL SENSES SYSTEM                                                                                                              
                                                                                                                                    
   Zymbal's Gland                                     (1)          (1)                       (2)                                    
      Adenoma                                                                                 1 (50%)                               
      Carcinoma                                        1 (100%)     1 (100%)                  1 (50%)                               
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                                                             Page  10                                                               
NTP Experiment-Test: 05136-07  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                            CHLOROPRENE                                        Date: 09/13/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 15:36:30  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS MALE                     CONTROL      12.8 PPM     32 PPM       80 PPM                                    
                                                                                                                                    
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 URINARY SYSTEM                                                                                                                     
                                                                                                                                    
   Kidney                                             (50)         (50)         (50)         (50)                                   
      Histiocytic Sarcoma                                                                     1 (2%)                                
      Mesenchymal Tumor NOS                                                                   1 (2%)                                
      Bilateral, Renal Tubule, Adenoma                              1 (2%)                                                          
      Renal Tubule, Adenoma                                                      1 (2%)       2 (4%)                                
      Transitional Epithelium, Carcinoma                            1 (2%)                                                          
   Urinary Bladder                                    (50)         (50)         (50)         (49)                                   
      Histiocytic Sarcoma                                                                     1 (2%)                                
      Transitional Epithelium, Carcinoma                                         1 (2%)                                             
      Transitional Epithelium, Papilloma                                                      1 (2%)                                
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SYSTEMIC LESIONS                                                                                                                   
   Multiple Organs                                   *(50)        *(50)        *(50)        *(50)                                   
      Histiocytic Sarcoma                                                                     2 (4%)                                
      Leukemia Mononuclear                            33 (66%)     34 (68%)     29 (58%)     27 (54%)                               
      Mesothelioma Malignant                                        1 (2%)       5 (10%)      3 (6%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
     *   Number of animals with any tissue examined microscopically                                                                 
                                                             Page  11                                                               
NTP Experiment-Test: 05136-07  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                            CHLOROPRENE                                        Date: 09/13/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 15:36:30  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS MALE                     CONTROL      12.8 PPM     32 PPM       80 PPM                                    
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
TUMOR SUMMARY                                                                                                                       
                                                                                                                                    
   Total Animals with Primary Neoplasms (b)            50          50          50          50                                       
     Total Primary Neoplasms                          166         181         176         180                                       
                                                                                                                                    
   Total Animals with Benign Neoplasms                 50          50          50          48                                       
     Total Benign Neoplasms                           118         123         121         133                                       
                                                                                                                                    
   Total Animals with Malignant Neoplasms              40          37          37          36                                       
     Total Malignant Neoplasms                         47          58          55          46                                       
                                                                                                                                    
   Total Animals with Metastatic Neoplasms                          1           2           2                                       
     Total Metastatic Neoplasm                                      1           5           2                                       
                                                                                                                                    
   Total Animals with Malignant Neoplasms                                                                                           
   Uncertain Primary Site                                                                                                           
                                                                                                                                    
   Total Animals with Neoplasms Uncertain-                                                                                          
   Benign or Malignant                                  1                                   1                                       
     Total Uncertain Neoplasms                          1                                   1                                       
                                                                                                                                    
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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.