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TDMS Study 05210-03 Pathology Tables

NTP Experiment-Test: 05210-03  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                            ETHYLBENZENE                                       Date: 03/14/96
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 11:28:43

                                                           CORE STUDY




       Facility:  I. I. T. Research Institute

       Chemical CAS #:  100-41-4

       Lock Date:  10/02/92

       Cage Range:  All

       Reasons For Removal:    All

       Removal Date Range:     All

       Treatment Groups:       Include All


































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

                                                              Page   1

NTP Experiment-Test: 05210-03  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                            ETHYLBENZENE                                       Date: 03/14/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 11:28:43  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS FEMALE                   CONTROL      75 PPM       250          750                                       
                                                                             PPM          PPM                                       
____________________________________________________________________________________________________________________________________
                                                                                                                                    
DISPOSITION SUMMARY                                                                                                                 
  Animals Initially in Study                          50           50           50           50                                     
  Early Deaths                                                                                                                      
    Moribund Sacrifice                                 7           14            8            6                                     
    Natural Death                                     12            5            8            8                                     
  Survivors                                                                                                                         
    Terminal Sacrifice                                30           31           34           35                                     
    Natural Death                                      1                                                                            
  Missing                                                                                     1                                     
  Animals Examined Microscopically                    50           50           50           49                                     
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ALIMENTARY SYSTEM                                                                                                                  
                                                                                                                                    
   Intestine Large, Colon                             (47)         (49)         (48)         (49)                                   
   Intestine Large, Rectum                            (49)         (50)         (47)         (49)                                   
      Polyp Adenomatous                                                          1 (2%)                                             
   Intestine Large, Cecum                             (44)         (50)         (47)         (49)                                   
   Intestine Small, Duodenum                          (47)         (48)         (47)         (48)                                   
   Intestine Small, Jejunum                           (41)         (49)         (47)         (45)                                   
   Intestine Small, Ileum                             (41)         (48)         (47)         (46)                                   
   Liver                                              (50)         (50)         (50)         (49)                                   
      Histiocytic Sarcoma                              1 (2%)                                                                       
   Mesentery                                          (7)          (4)          (6)          (7)                                    
   Oral Mucosa                                                                               (1)                                    
      Pharyngeal, Squamous Cell Papilloma                                                     1 (100%)                              
   Pancreas                                           (49)         (50)         (50)         (49)                                   
      Histiocytic Sarcoma                              1 (2%)                                                                       
   Salivary Glands                                    (50)         (50)         (50)         (49)                                   
   Stomach, Forestomach                               (49)         (50)         (50)         (49)                                   
   Stomach, Glandular                                 (49)         (49)         (49)         (49)                                   
   Tongue                                                                       (1)          (1)                                    
      Schwannoma Malignant                                                                    1 (100%)                              
      Squamous Cell Papilloma                                                    1 (100%)                                           
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 CARDIOVASCULAR SYSTEM                                                                                                              
                                                                                                                                    
   Heart                                              (50)         (50)         (50)         (49)                                   
____________________________________________________________________________________________________________________________________
                                                                                                                                    
                                                             Page   2                                                               
NTP Experiment-Test: 05210-03  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                            ETHYLBENZENE                                       Date: 03/14/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 11:28:43  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS FEMALE                   CONTROL      75 PPM       250          750                                       
                                                                             PPM          PPM                                       
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ENDOCRINE SYSTEM                                                                                                                   
                                                                                                                                    
   Adrenal Cortex                                     (50)         (50)         (50)         (49)                                   
      Adenoma                                                       1 (2%)       1 (2%)                                             
      Carcinoma                                                                  1 (2%)                                             
   Adrenal Medulla                                    (50)         (50)         (50)         (49)                                   
      Pheochromocytoma Malignant                                    1 (2%)       2 (4%)                                             
      Pheochromocytoma Benign                          2 (4%)                                                                       
      Bilateral, Pheochromocytoma Benign                            2 (4%)                                                          
   Islets, Pancreatic                                 (50)         (50)         (50)         (49)                                   
      Adenoma                                          1 (2%)                    1 (2%)       1 (2%)                                
   Pituitary Gland                                    (49)         (49)         (50)         (49)                                   
      Pars Distalis, Adenoma                          27 (55%)     17 (35%)     24 (48%)     24 (49%)                               
      Pars Distalis, Adenoma, Multiple                 3 (6%)       6 (12%)      1 (2%)       3 (6%)                                
      Pars Distalis, Carcinoma                                      1 (2%)       1 (2%)                                             
   Thyroid Gland                                      (48)         (50)         (50)         (49)                                   
      Bilateral, C-Cell, Adenoma                                    1 (2%)                                                          
      C-Cell, Adenoma                                  2 (4%)       3 (6%)       2 (4%)       3 (6%)                                
      C-Cell, Carcinoma                                                                       1 (2%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENERAL BODY SYSTEM                                                                                                                
                                                                                                                                    
   None                                                                                                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENITAL SYSTEM                                                                                                                     
                                                                                                                                    
   Clitoral Gland                                     (47)         (49)         (48)         (47)                                   
      Adenoma                                          2 (4%)                                                                       
      Carcinoma                                        1 (2%)                    1 (2%)                                             
   Ovary                                              (50)         (50)         (50)         (49)                                   
      Histiocytic Sarcoma                                                                     1 (2%)                                
   Uterus                                             (50)         (50)         (50)         (49)                                   
      Polyp Stromal                                    2 (4%)       3 (6%)       4 (8%)       3 (6%)                                
      Bilateral, Polyp Stromal                                                   1 (2%)                                             
      Endometrium, Sarcoma Stromal                                  1 (2%)                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 HEMATOPOIETIC SYSTEM                                                                                                               
                                                                                                                                    
   Bone Marrow                                        (49)         (50)         (50)         (49)                                   
   Lymph Node                                         (3)          (3)          (4)          (4)                                    
      Lumbar, Histiocytic Sarcoma                      1 (33%)                                                                      
   Lymph Node, Bronchial                              (37)         (34)         (41)         (38)                                   
   Lymph Node, Mandibular                             (49)         (50)         (50)         (49)                                   
   Lymph Node, Mesenteric                             (49)         (50)         (50)         (49)                                   
   Lymph Node, Mediastinal                            (49)         (49)         (50)         (49)                                   
                                                             Page   3                                                               
NTP Experiment-Test: 05210-03  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                            ETHYLBENZENE                                       Date: 03/14/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 11:28:43  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS FEMALE                   CONTROL      75 PPM       250          750                                       
                                                                             PPM          PPM                                       
____________________________________________________________________________________________________________________________________
                                                                                                                                    
HEMATOPOIETIC SYSTEM - cont                                                                                                         
      Rhabdomyosarcoma, Metastatic, Uncertain                                                                                       
          Primary Site                                                           1 (2%)                                             
   Spleen                                             (49)         (50)         (49)         (49)                                   
   Thymus                                             (48)         (47)         (47)         (47)                                   
      Rhabdomyosarcoma, Metastatic, Uncertain                                                                                       
          Primary Site                                                           1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 INTEGUMENTARY SYSTEM                                                                                                               
                                                                                                                                    
   Mammary Gland                                      (48)         (50)         (49)         (49)                                   
      Adenoma                                          1 (2%)       2 (4%)                    1 (2%)                                
      Carcinoma                                        2 (4%)       1 (2%)       2 (4%)                                             
      Carcinoma, Multiple                              1 (2%)                                 1 (2%)                                
      Fibroadenoma                                    13 (27%)     18 (36%)     18 (37%)     15 (31%)                               
      Fibroadenoma, Multiple                           6 (13%)      1 (2%)       3 (6%)       6 (12%)                               
   Skin                                               (50)         (50)         (50)         (49)                                   
      Squamous Cell Carcinoma                                                    1 (2%)                                             
      Squamous Cell Papilloma                                                    2 (4%)                                             
      Sebaceous Gland, Carcinoma                                                              1 (2%)                                
      Subcutaneous Tissue, Fibroma                     1 (2%)                                                                       
      Subcutaneous Tissue, Fibrosarcoma                             1 (2%)                                                          
      Subcutaneous Tissue, Lipoma                                   1 (2%)                                                          
      Subcutaneous Tissue, Sarcoma                                  1 (2%)                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 MUSCULOSKELETAL SYSTEM                                                                                                             
                                                                                                                                    
   Skeletal Muscle                                                 (1)                                                              
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 NERVOUS SYSTEM                                                                                                                     
                                                                                                                                    
   Brain                                              (50)         (50)         (50)         (49)                                   
      Astrocytoma Malignant                            1 (2%)                                                                       
      Carcinoma, Metastatic, Pituitary Gland                        1 (2%)       1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 RESPIRATORY SYSTEM                                                                                                                 
                                                                                                                                    
   Larynx                                             (45)         (43)         (44)         (45)                                   
   Lung                                               (50)         (50)         (50)         (49)                                   
      Alveolar/Bronchiolar Adenoma                     1 (2%)                    1 (2%)                                             
      Alveolar/Bronchiolar Adenoma, Multiple                        1 (2%)                                                          
      Carcinoma, Metastatic, Mammary Gland                                       1 (2%)                                             
      Histiocytic Sarcoma                              1 (2%)                                                                       
      Sarcoma, Metastatic, Uncertain Primary Site                   1 (2%)                                                          
                                                             Page   4                                                               
NTP Experiment-Test: 05210-03  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                            ETHYLBENZENE                                       Date: 03/14/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 11:28:43  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS FEMALE                   CONTROL      75 PPM       250          750                                       
                                                                             PPM          PPM                                       
____________________________________________________________________________________________________________________________________
                                                                                                                                    
RESPIRATORY SYSTEM - cont                                                                                                           
      Mediastinum, Sarcoma, Metastatic, Uncertain                                                                                   
          Primary Site                                              1 (2%)                                                          
   Nose                                               (50)         (50)         (50)         (49)                                   
      Glands, Adenoma                                               1 (2%)                                                          
   Trachea                                            (50)         (50)         (50)         (49)                                   
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SPECIAL SENSES SYSTEM                                                                                                              
                                                                                                                                    
   Ear                                                (3)                                                                           
      External Ear, Sarcoma                            1 (33%)                                                                      
   Zymbal's Gland                                     (1)          (1)                                                              
      Adenoma                                          1 (100%)                                                                     
      Carcinoma                                                     1 (100%)                                                        
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 URINARY SYSTEM                                                                                                                     
                                                                                                                                    
   Kidney                                             (50)         (50)         (50)         (49)                                   
      Renal Tubule, Adenoma                                                                   1 (2%)                                
   Urinary Bladder                                    (48)         (49)         (49)         (48)                                   
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SYSTEMIC LESIONS                                                                                                                   
   Multiple Organs                                   *(50)        *(50)        *(50)        *(49)                                   
      Histiocytic Sarcoma                              2 (4%)                                 1 (2%)                                
      Leukemia Granulocytic                                         1 (2%)                                                          
      Leukemia Mononuclear                            13 (26%)     18 (36%)     16 (32%)     11 (22%)                               
      Lymphoma Malignant                               1 (2%)       1 (2%)                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
     *   Number of animals with any tissue examined microscopically                                                                 
                                                             Page   5                                                               
NTP Experiment-Test: 05210-03  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                            ETHYLBENZENE                                       Date: 03/14/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 11:28:43  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS FEMALE                   CONTROL      75 PPM       250          750                                       
                                                                             PPM          PPM                                       
____________________________________________________________________________________________________________________________________
                                                                                                                                    
TUMOR SUMMARY                                                                                                                       
                                                                                                                                    
   Total Animals with Primary Neoplasms (b)            42          45          43          46                                       
     Total Primary Neoplasms                           84          84          84          74                                       
                                                                                                                                    
   Total Animals with Benign Neoplasms                 37          39          37          39                                       
     Total Benign Neoplasms                            62          57          60          58                                       
                                                                                                                                    
   Total Animals with Malignant Neoplasms              20          24          21          14                                       
     Total Malignant Neoplasms                         22          27          24          16                                       
                                                                                                                                    
   Total Animals with Metastatic Neoplasms                          2           3                                                   
     Total Metastatic Neoplasm                                      3           4                                                   
                                                                                                                                    
   Total Animals with Malignant Neoplasms                           1           1                                                   
   Uncertain Primary Site                                                                                                           
                                                                                                                                    
   Total Animals with Neoplasms Uncertain-                                                                                          
   Benign or Malignant                                                                                                              
     Total Uncertain Neoplasms                                                                                                      
                                                                                                                                    
____________________________________________________________________________________________________________________________________
a  Number of animals examined microscopically at site and number of animals with lesion                                             
b  Primary tumors: all tumors except metastatic tumors                                                                              
                                                             Page   6                                                               
NTP Experiment-Test: 05210-03  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                            ETHYLBENZENE                                       Date: 03/14/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 11:28:43  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS MALE                     CONTROL      75 PPM       250          750                                       
                                                                             PPM          PPM                                       
____________________________________________________________________________________________________________________________________
                                                                                                                                    
DISPOSITION SUMMARY                                                                                                                 
  Animals Initially in Study                          50           50           50           50                                     
  Early Deaths                                                                                                                      
    Natural Death                                      7           16           11           22                                     
    Moribund Sacrifice                                28           20           26           26                                     
  Survivors                                                                                                                         
    Terminal Sacrifice                                15           14           13            2                                     
  Animals Examined Microscopically                    50           50           50           50                                     
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ALIMENTARY SYSTEM                                                                                                                  
                                                                                                                                    
   Esophagus                                          (50)         (50)         (50)         (50)                                   
   Intestine Large, Colon                             (50)         (48)         (48)         (48)                                   
      Sarcoma                                          1 (2%)                                                                       
   Intestine Large, Rectum                            (48)         (49)         (48)         (48)                                   
   Intestine Large, Cecum                             (46)         (44)         (46)         (39)                                   
   Intestine Small, Duodenum                          (48)         (48)         (50)         (50)                                   
   Intestine Small, Jejunum                           (42)         (39)         (44)         (34)                                   
   Intestine Small, Ileum                             (45)         (44)         (45)         (37)                                   
   Liver                                              (50)         (50)         (50)         (49)                                   
      Hepatocellular Adenoma                                        3 (6%)                                                          
      Histiocytic Sarcoma                                           1 (2%)                                                          
      Osteosarcoma, Metastatic, Spleen                 1 (2%)                                                                       
   Mesentery                                          (4)          (5)          (3)          (3)                                    
      Lipoma                                                                     1 (33%)                                            
      Sarcoma                                          1 (25%)                                                                      
   Oral Mucosa                                        (2)                       (1)          (1)                                    
      Pharyngeal, Squamous Cell Papilloma              2 (100%)                  1 (100%)     1 (100%)                              
   Pancreas                                           (50)         (49)         (50)         (50)                                   
      Duct, Carcinoma                                               1 (2%)                                                          
   Salivary Glands                                    (50)         (49)         (50)         (50)                                   
   Stomach, Forestomach                               (50)         (50)         (50)         (50)                                   
   Stomach, Glandular                                 (50)         (49)         (50)         (50)                                   
   Tongue                                             (1)                                                                           
      Squamous Cell Papilloma                          1 (100%)                                                                     
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 CARDIOVASCULAR SYSTEM                                                                                                              
                                                                                                                                    
   Heart                                              (50)         (50)         (50)         (50)                                   
____________________________________________________________________________________________________________________________________
                                                                                                                                    
                                                             Page   7                                                               
NTP Experiment-Test: 05210-03  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                            ETHYLBENZENE                                       Date: 03/14/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 11:28:43  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS MALE                     CONTROL      75 PPM       250          750                                       
                                                                             PPM          PPM                                       
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ENDOCRINE SYSTEM                                                                                                                   
                                                                                                                                    
   Adrenal Cortex                                     (50)         (50)         (50)         (50)                                   
      Osteosarcoma, Metastatic, Spleen                 1 (2%)                                                                       
   Adrenal Medulla                                    (50)         (50)         (49)         (48)                                   
      Osteosarcoma, Metastatic, Spleen                 1 (2%)                                                                       
      Pheochromocytoma Malignant                                    1 (2%)                    2 (4%)                                
      Pheochromocytoma Benign                          6 (12%)     10 (20%)      6 (12%)      9 (19%)                               
      Bilateral, Pheochromocytoma Benign               7 (14%)      3 (6%)       3 (6%)       3 (6%)                                
   Islets, Pancreatic                                 (50)         (50)         (50)         (50)                                   
      Adenoma                                          3 (6%)       4 (8%)       4 (8%)       4 (8%)                                
      Carcinoma                                        2 (4%)       1 (2%)                                                          
   Parathyroid Gland                                  (45)         (46)         (46)         (46)                                   
      Adenoma                                                       1 (2%)                                                          
   Pituitary Gland                                    (49)         (50)         (50)         (45)                                   
      Pars Distalis, Adenoma                          23 (47%)     18 (36%)     18 (36%)     18 (40%)                               
      Pars Distalis, Adenoma, Multiple                 2 (4%)       1 (2%)       1 (2%)                                             
   Thyroid Gland                                      (50)         (49)         (50)         (50)                                   
      Bilateral, C-Cell, Adenoma                       2 (4%)                                                                       
      C-Cell, Adenoma                                  1 (2%)       6 (12%)      3 (6%)       2 (4%)                                
      C-Cell, Carcinoma                                2 (4%)                                                                       
      Follicular Cell, Carcinoma                       1 (2%)       1 (2%)       1 (2%)       1 (2%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENERAL BODY SYSTEM                                                                                                                
                                                                                                                                    
   Peritoneum                                                      (1)                                                              
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENITAL SYSTEM                                                                                                                     
                                                                                                                                    
   Epididymis                                         (50)         (50)         (50)         (50)                                   
   Preputial Gland                                    (49)         (50)         (49)         (50)                                   
      Adenoma                                          3 (6%)       1 (2%)       1 (2%)       2 (4%)                                
      Bilateral, Adenoma                                                                      2 (4%)                                
   Prostate                                           (50)         (50)         (50)         (50)                                   
   Seminal Vesicle                                    (49)         (49)         (50)         (50)                                   
   Testes                                             (50)         (50)         (50)         (50)                                   
      Bilateral, Interstitial Cell, Adenoma           27 (54%)     23 (46%)     32 (64%)     40 (80%)                               
      Interstitial Cell, Adenoma                       9 (18%)     10 (20%)      8 (16%)      4 (8%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 HEMATOPOIETIC SYSTEM                                                                                                               
                                                                                                                                    
   Bone Marrow                                        (49)         (49)         (50)         (50)                                   
      Histiocytic Sarcoma                                           1 (2%)                                                          
   Lymph Node                                         (9)          (8)          (9)          (14)                                   
   Lymph Node, Bronchial                              (44)         (34)         (39)         (28)                                   
                                                             Page   8                                                               
NTP Experiment-Test: 05210-03  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                            ETHYLBENZENE                                       Date: 03/14/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 11:28:43  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS MALE                     CONTROL      75 PPM       250          750                                       
                                                                             PPM          PPM                                       
____________________________________________________________________________________________________________________________________
                                                                                                                                    
HEMATOPOIETIC SYSTEM - cont                                                                                                         
      Histiocytic Sarcoma                                           1 (3%)                                                          
   Lymph Node, Mandibular                             (47)         (48)         (49)         (50)                                   
   Lymph Node, Mesenteric                             (49)         (50)         (50)         (50)                                   
      Histiocytic Sarcoma                                           1 (2%)                                                          
   Lymph Node, Mediastinal                            (48)         (48)         (50)         (47)                                   
      Histiocytic Sarcoma                                           1 (2%)                                                          
   Spleen                                             (50)         (49)         (50)         (50)                                   
      Histiocytic Sarcoma                                           1 (2%)                                                          
      Osteosarcoma                                     1 (2%)                                                                       
   Thymus                                             (46)         (44)         (46)         (44)                                   
      Histiocytic Sarcoma                                           1 (2%)                                                          
      Thymoma Benign                                                             1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 INTEGUMENTARY SYSTEM                                                                                                               
                                                                                                                                    
   Mammary Gland                                      (46)         (47)         (46)         (49)                                   
      Adenoma                                                                    1 (2%)                                             
      Fibroadenoma                                     2 (4%)       2 (4%)       2 (4%)                                             
      Fibroadenoma, Multiple                                        1 (2%)                                                          
      Fibroma                                                       2 (4%)                                                          
   Skin                                               (50)         (50)         (50)         (50)                                   
      Basal Cell Adenoma                                                         1 (2%)                                             
      Basal Cell Carcinoma                                                                    1 (2%)                                
      Keratoacanthoma                                  3 (6%)       2 (4%)       2 (4%)       2 (4%)                                
      Squamous Cell Papilloma                          2 (4%)       1 (2%)       1 (2%)                                             
      Pinna, Schwannoma Benign                                      1 (2%)                                                          
      Pinna, Schwannoma Malignant                                                1 (2%)                                             
      Sebaceous Gland, Adenoma                                                   1 (2%)                                             
      Subcutaneous Tissue, Fibroma                     1 (2%)       1 (2%)       3 (6%)                                             
      Subcutaneous Tissue, Fibrosarcoma                             1 (2%)                                                          
      Subcutaneous Tissue, Lipoma                                                             1 (2%)                                
      Subcutaneous Tissue, Myxoma                                                1 (2%)                                             
      Subcutaneous Tissue, Sarcoma                                  2 (4%)                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 MUSCULOSKELETAL SYSTEM                                                                                                             
                                                                                                                                    
   Bone                                               (49)         (50)         (50)         (50)                                   
      Histiocytic Sarcoma                                           1 (2%)                                                          
      Turbinate, Chondroma                                                       1 (2%)                                             
   Skeletal Muscle                                    (1)          (1)                       (1)                                    
      Histiocytic Sarcoma                                           1 (100%)                                                        
      Osteosarcoma, Metastatic, Spleen                 1 (100%)                                                                     
      Sarcoma                                                                                 1 (100%)                              
____________________________________________________________________________________________________________________________________
                                                                                                                                    
                                                             Page   9                                                               
NTP Experiment-Test: 05210-03  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                            ETHYLBENZENE                                       Date: 03/14/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 11:28:43  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS MALE                     CONTROL      75 PPM       250          750                                       
                                                                             PPM          PPM                                       
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 NERVOUS SYSTEM                                                                                                                     
                                                                                                                                    
   Brain                                              (50)         (50)         (50)         (50)                                   
      Glioma Malignant                                                           1 (2%)       1 (2%)                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 RESPIRATORY SYSTEM                                                                                                                 
                                                                                                                                    
   Larynx                                             (40)         (44)         (41)         (35)                                   
   Lung                                               (50)         (50)         (50)         (50)                                   
      Alveolar/Bronchiolar Adenoma                     2 (4%)       1 (2%)                    1 (2%)                                
      Alveolar/Bronchiolar Carcinoma                   1 (2%)                                                                       
      Carcinoma, Metastatic, Thyroid Gland             2 (4%)                                                                       
      Histiocytic Sarcoma                                           1 (2%)                                                          
      Osteosarcoma, Metastatic, Spleen                 1 (2%)                                                                       
      Mediastinum, Osteosarcoma, Metastatic, Spleen    1 (2%)                                                                       
   Nose                                               (49)         (49)         (50)         (50)                                   
   Trachea                                            (50)         (50)         (50)         (50)                                   
      Leiomyosarcoma                                                             1 (2%)                                             
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 SPECIAL SENSES SYSTEM                                                                                                              
                                                                                                                                    
   Harderian Gland                                                              (1)                                                 
      Carcinoma                                                                  1 (100%)                                           
   Zymbal's Gland                                     (1)                       (1)          (1)                                    
      Carcinoma                                        1 (100%)                  1 (100%)                                           
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 URINARY SYSTEM                                                                                                                     
                                                                                                                                    
   Kidney                                             (50)         (50)         (50)         (50)                                   
      Histiocytic Sarcoma                                           1 (2%)                                                          
      Lipoma                                           1 (2%)                                                                       
      Renal Tubule, Adenoma                                         3 (6%)       2 (4%)       4 (8%)                                
      Renal Tubule, Carcinoma                                                    1 (2%)       3 (6%)                                
   Urinary Bladder                                    (49)         (49)         (50)         (49)                                   
      Transitional Epithelium, Papilloma                            1 (2%)                                                          
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SYSTEMIC LESIONS                                                                                                                   
   Multiple Organs                                   *(50)        *(50)        *(50)        *(50)                                   
      Histiocytic Sarcoma                                           1 (2%)                                                          
      Leukemia Mononuclear                            27 (54%)     26 (52%)     32 (64%)      9 (18%)                               
      Mesothelioma Malignant                                        2 (4%)       1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
     *   Number of animals with any tissue examined microscopically                                                                 
                                                             Page  10                                                               
NTP Experiment-Test: 05210-03  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                            ETHYLBENZENE                                       Date: 03/14/96  
Route: RESPIRATORY EXPOSURE WHOLE BODY                                                                            Time: 11:28:43  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS MALE                     CONTROL      75 PPM       250          750                                       
                                                                             PPM          PPM                                       
____________________________________________________________________________________________________________________________________
                                                                                                                                    
TUMOR SUMMARY                                                                                                                       
                                                                                                                                    
   Total Animals with Primary Neoplasms (b)            49          45          50          50                                       
     Total Primary Neoplasms                          134         131         134         111                                       
                                                                                                                                    
   Total Animals with Benign Neoplasms                 48          44          48          48                                       
     Total Benign Neoplasms                            97          95          94          93                                       
                                                                                                                                    
   Total Animals with Malignant Neoplasms              33          32          37          17                                       
     Total Malignant Neoplasms                         37          36          40          18                                       
                                                                                                                                    
   Total Animals with Metastatic Neoplasms              3                                                                           
     Total Metastatic Neoplasm                          8                                                                           
                                                                                                                                    
   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  11                                                               
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