National Toxicology Program

National Toxicology Program
https://ntp.niehs.nih.gov/go/3462

TDMS Study 05040-01 Pathology Tables


                              INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)
                                                            HYDROQUINONE


NTP Experiment-Test: 05040-01                                                                                     Report: PEIRPT05
Study Type: CHRONIC                                                                                               Date: 09/05/94
Route: GAVAGE                                                                                                     Time: 10:19:35




       Facility:  American Biogenics Corp.

       Chemical CAS #:  000123319

       Lock Date:  None

       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: 05040-01  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 09/05/94  
Route: GAVAGE                                                                                                     Time: 10:19:35  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS FEMALE                   VEHICLE      25 MG/KG     50 MG/KG                                               
                                                   CONTROL                                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
DISPOSITION SUMMARY                                                                                                                 
  Animals Initially in Study                          65           65           65                                                  
  Scheduled Sacrifice                                 10           10           10                                                  
  Early Deaths                                                                                                                      
    Moribund                                          14           19           14                                                  
    Dead                                               1            6            6                                                  
    Gavage Death                                                    3            3                                                  
  Survivors                                                                                                                         
    Terminal Sacrifice                                39           27           31                                                  
    Dead                                               1                                                                            
    Accident                                                                     1                                                  
  Animals Examined Microscopically                    55           55           55                                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ALIMENTARY SYSTEM                                                                                                                  
                                                                                                                                    
   Intestine Large, Cecum                             (53)         (24)         (53)                                                
   Intestine Large, Colon                             (55)         (26)         (54)                                                
   Intestine Large, Rectum                            (55)         (28)         (51)                                                
   Intestine Small, Duodenum                          (55)         (28)         (55)                                                
   Intestine Small, Ileum                             (54)         (24)         (53)                                                
      Sarcoma                                                                    1 (2%)                                             
   Intestine Small, Jejunum                           (54)         (23)         (51)                                                
      Cystadenocarcinoma                                                         1 (2%)                                             
      Sarcoma                                                                    1 (2%)                                             
   Liver                                              (55)         (55)         (55)                                                
   Mesentery                                          (7)          (13)         (16)                                                
      Pheochromocytoma Malignant, Extension,                                                                                        
          Metastatic, Adrenal Gland                                              1 (6%)                                             
   Pancreas                                           (55)         (28)         (55)                                                
   Salivary Glands                                    (55)         (26)         (55)                                                
   Stomach, Forestomach                               (55)         (28)         (54)                                                
   Stomach, Glandular                                 (55)         (28)         (54)                                                
   Tongue                                                          (1)                                                              
      Squamous Cell Papilloma                                       1 (100%)                                                        
   Tooth                                              (3)          (3)          (5)                                                 
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 CARDIOVASCULAR SYSTEM                                                                                                              
                                                                                                                                    
   Heart                                              (55)         (28)         (55)                                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
                                                             Page   2                                                               
NTP Experiment-Test: 05040-01  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 09/05/94  
Route: GAVAGE                                                                                                     Time: 10:19:35  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS FEMALE                   VEHICLE      25 MG/KG     50 MG/KG                                               
                                                   CONTROL                                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ENDOCRINE SYSTEM                                                                                                                   
                                                                                                                                    
   Adrenal Gland, Cortex                              (55)         (55)         (55)                                                
      Adenoma                                                                    1 (2%)                                             
   Adrenal Gland, Medulla                             (54)         (55)         (54)                                                
      Pheochromocytoma Malignant                       1 (2%)       1 (2%)       1 (2%)                                             
      Pheochromocytoma Complex                                      1 (2%)                                                          
      Pheochromocytoma Benign                          2 (4%)                    4 (7%)                                             
      Bilateral, Pheochromocytoma Benign                            1 (2%)                                                          
   Islets, Pancreatic                                 (53)         (28)         (55)                                                
   Parathyroid Gland                                  (54)         (22)         (54)                                                
   Pituitary Gland                                    (54)         (54)         (54)                                                
      Meningioma Malignant, Metastatic                                           1 (2%)                                             
      Pars Distalis, Adenoma                          23 (43%)     21 (39%)     16 (30%)                                            
      Pars Distalis, Carcinoma                         1 (2%)       1 (2%)                                                          
   Thyroid Gland                                      (55)         (54)         (55)                                                
      Bilateral, C-Cell, Adenoma                       1 (2%)                                                                       
      C-Cell, Adenoma                                  8 (15%)      3 (6%)       5 (9%)                                             
      C-Cell, Carcinoma                                4 (7%)       1 (2%)       3 (5%)                                             
      Follicular Cell, Adenocarcinoma                  1 (2%)       1 (2%)                                                          
      Follicular Cell, Adenoma                                      1 (2%)                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENERAL BODY SYSTEM                                                                                                                
                                                                                                                                    
   None                                                                                                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENITAL SYSTEM                                                                                                                     
                                                                                                                                    
   Clitoral Gland                                     (51)         (24)         (52)                                                
      Adenoma                                          4 (8%)       3 (13%)      9 (17%)                                            
   Ovary                                              (55)         (29)         (55)                                                
      Granulosa Cell Tumor Malignant                   1 (2%)       1 (3%)                                                          
      Luteoma                                                       1 (3%)                                                          
   Oviduct                                                                      (2)                                                 
   Uterus                                             (55)         (55)         (55)                                                
      Leiomyosarcoma                                                1 (2%)                                                          
      Polyp Stromal                                   12 (22%)      5 (9%)       9 (16%)                                            
      Bilateral, Polyp Stromal                                      1 (2%)                                                          
      Endometrium, Adenocarcinoma                                   1 (2%)                                                          
      Endometrium, Sarcoma Stromal                     1 (2%)       1 (2%)                                                          
   Vagina                                             (2)          (1)          (1)                                                 
      Squamous Cell Carcinoma                                                    1 (100%)                                           
____________________________________________________________________________________________________________________________________
                                                                                                                                    
                                                             Page   3                                                               
NTP Experiment-Test: 05040-01  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 09/05/94  
Route: GAVAGE                                                                                                     Time: 10:19:35  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS FEMALE                   VEHICLE      25 MG/KG     50 MG/KG                                               
                                                   CONTROL                                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 HEMATOPOIETIC SYSTEM                                                                                                               
                                                                                                                                    
   Blood                                              (8)          (10)         (18)                                                
   Bone Marrow                                        (55)         (28)         (55)                                                
   Lymph Node                                         (55)         (28)         (55)                                                
   Lymph Node, Mandibular                             (55)         (26)         (52)                                                
   Lymph Node, Mesenteric                             (53)         (28)         (54)                                                
   Spleen                                             (55)         (55)         (55)                                                
   Thymus                                             (52)         (27)         (51)                                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 INTEGUMENTARY SYSTEM                                                                                                               
                                                                                                                                    
   Mammary Gland                                      (55)         (55)         (54)                                                
      Adenocarcinoma                                   2 (4%)                    1 (2%)                                             
      Adenocarcinoma, Multiple                         1 (2%)                                                                       
      Adenoma                                                       2 (4%)                                                          
      Fibroadenoma                                    28 (51%)     22 (40%)     21 (39%)                                            
      Fibroadenoma, Multiple                           1 (2%)                    1 (2%)                                             
   Skin                                               (55)         (30)         (55)                                                
      Basal Cell Adenoma                                            1 (3%)                                                          
      Keratoacanthoma                                               1 (3%)       2 (4%)                                             
      Squamous Cell Papilloma                                                    1 (2%)                                             
      Subcutaneous Tissue, Sarcoma                                               1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 MUSCULOSKELETAL SYSTEM                                                                                                             
                                                                                                                                    
   Bone                                               (54)         (28)         (55)                                                
      Cartilage, Adenocarcinoma, Extension,                                                                                         
          Metastatic, Thyroid Gland                                 1 (4%)                                                          
   Skeletal Muscle                                    (1)          (2)          (2)                                                 
      Pheochromocytoma Malignant, Extension,                                                                                        
          Metastatic, Adrenal Gland                                              1 (50%)                                            
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 NERVOUS SYSTEM                                                                                                                     
                                                                                                                                    
   Brain                                              (55)         (28)         (55)                                                
      Astrocytoma Malignant                                         1 (4%)                                                          
      Meninges, Meningioma Malignant                                             1 (2%)                                             
      Pons, Carcinoma, Metastatic                      1 (2%)                                                                       
   Spinal Cord                                        (8)          (7)          (12)                                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
                                                             Page   4                                                               
NTP Experiment-Test: 05040-01  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 09/05/94  
Route: GAVAGE                                                                                                     Time: 10:19:35  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS FEMALE                   VEHICLE      25 MG/KG     50 MG/KG                                               
                                                   CONTROL                                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 RESPIRATORY SYSTEM                                                                                                                 
                                                                                                                                    
   Lung                                               (55)         (29)         (55)                                                
      Alveolar/Bronchiolar Carcinoma                                1 (3%)       1 (2%)                                             
      Carcinoma, Metastatic, Thyroid Gland                                       1 (2%)                                             
      Pheochromocytoma Malignant, Metastatic,                                                                                       
          Adrenal Gland                                                          1 (2%)                                             
   Nose                                               (55)         (28)         (55)                                                
   Trachea                                            (55)         (28)         (55)                                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SPECIAL SENSES SYSTEM                                                                                                              
                                                                                                                                    
   Zymbal's Gland                                                               (1)                                                 
      Carcinoma                                                                  1 (100%)                                           
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 URINARY SYSTEM                                                                                                                     
                                                                                                                                    
   Kidney                                             (55)         (55)         (55)                                                
   Urinary Bladder                                    (55)         (27)         (51)                                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 SYSTEMIC LESIONS                                                                                                                   
   Multiple Organs                                   *(55)        *(55)        *(55)                                                
      Leukemia Mononuclear                             9 (16%)     15 (27%)     22 (40%)                                            
____________________________________________________________________________________________________________________________________
                                                                                                                                    
     *   Number of animals with any tissue examined microscopically                                                                 
                                                             Page   5                                                               
NTP Experiment-Test: 05040-01  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 09/05/94  
Route: GAVAGE                                                                                                     Time: 10:19:35  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS FEMALE                   VEHICLE      25 MG/KG     50 MG/KG                                               
                                                   CONTROL                                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
TUMOR SUMMARY                                                                                                                       
                                                                                                                                    
   Total Animals with Primary Neoplasms (b)            47          49          50                                                   
     Total Primary Neoplasms                          100          89         104                                                   
                                                                                                                                    
   Total Animals with Benign Neoplasms                 44          41          42                                                   
     Total Benign Neoplasms                            79          63          69                                                   
                                                                                                                                    
   Total Animals with Malignant Neoplasms              18          24          32                                                   
     Total Malignant Neoplasms                         21          26          35                                                   
                                                                                                                                    
   Total Animals with Metastatic Neoplasms              1           1           3                                                   
     Total Metastatic Neoplasm                          1           1           5                                                   
                                                                                                                                    
   Total Animals with Malignant Neoplasms                                                                                           
   Uncertain Primary Site                                                                                                           
                                                                                                                                    
   Total Animals with Neoplasms Uncertain-                                                                                          
   Benign or Malignant                                                                                                              
     Total Uncertain Neoplasms                                                                                                      
                                                                                                                                    
____________________________________________________________________________________________________________________________________
a  Number of animals examined microscopically at site and number of animals with lesion                                             
b  Primary tumors: all tumors except metastatic tumors                                                                              
                                                             Page   6                                                               
NTP Experiment-Test: 05040-01  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 09/05/94  
Route: GAVAGE                                                                                                     Time: 10:19:35  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS MALE                     VEHICLE      25 MG/KG     50 MG/KG                                               
                                                   CONTROL                                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
DISPOSITION SUMMARY                                                                                                                 
  Animals Initially in Study                          65           65           65                                                  
  Scheduled Sacrifice                                 10           10           10                                                  
  Early Deaths                                                                                                                      
    Moribund                                          13           25           22                                                  
    Gavage Death                                       2            5            7                                                  
    Dead                                              13            7            8                                                  
  Survivors                                                                                                                         
    Terminal Sacrifice                                27           18           18                                                  
  Animals Examined Microscopically                    55           55           55                                                  
                                                                                                                                    
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ALIMENTARY SYSTEM                                                                                                                  
                                                                                                                                    
   Intestine Large, Cecum                             (50)         (34)         (50)                                                
   Intestine Large, Colon                             (51)         (35)         (53)                                                
      Serosa, Histiocytic Sarcoma, Metastatic          1 (2%)                                                                       
   Intestine Large, Rectum                            (53)         (32)         (52)                                                
   Intestine Small, Duodenum                          (52)         (35)         (55)                                                
      Serosa, Ileum, Jejunum, Histiocytic Sarcoma,                                                                                  
           Metastatic                                  1 (2%)                                                                       
   Intestine Small, Ileum                             (48)         (33)         (49)                                                
   Intestine Small, Jejunum                           (44)         (30)         (48)                                                
      Leiomyosarcoma                                   1 (2%)       1 (3%)                                                          
   Liver                                              (55)         (55)         (55)                                                
      Hepatocellular Adenoma                           3 (5%)                    1 (2%)                                             
      Histiocytic Sarcoma                                                        1 (2%)                                             
      Histiocytic Sarcoma, Metastatic                  2 (4%)       1 (2%)                                                          
      Leiomyosarcoma, Metastatic, Intestine Small      1 (2%)                                                                       
      Neoplastic Nodule                                             2 (4%)       1 (2%)                                             
      Bile Duct, Leiomyosarcoma, Extension,                                                                                         
          Metastatic, Intestine Small                               1 (2%)                                                          
   Mesentery                                          (12)         (16)         (9)                                                 
      Histiocytic Sarcoma, Metastatic                  2 (17%)                                                                      
      Leiomyosarcoma, Extension, Metastatic,                                                                                        
          Intestine Small                              1 (8%)       1 (6%)                                                          
   Pancreas                                           (53)         (36)         (54)                                                
      Histiocytic Sarcoma, Metastatic                  2 (4%)                                                                       
   Pharynx                                            (1)                                                                           
      Palate, Carcinoma, Extension, Metastatic,                                                                                     
           Zymbal's Gland                              1 (100%)                                                                     
   Salivary Glands                                    (54)         (37)         (55)                                                
   Stomach, Forestomach                               (55)         (36)         (55)                                                
      Serosa, Glandular, Histiocytic Sarcoma,                                                                                       
                                                             Page   7                                                               
NTP Experiment-Test: 05040-01  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 09/05/94  
Route: GAVAGE                                                                                                     Time: 10:19:35  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS MALE                     VEHICLE      25 MG/KG     50 MG/KG                                               
                                                   CONTROL                                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
ALIMENTARY SYSTEM - cont                                                                                                            
          Metastatic                                   1 (2%)                                                                       
   Stomach, Glandular                                 (54)         (34)         (55)                                                
   Tongue                                             (2)                                                                           
      Squamous Cell Papilloma                          1 (50%)                                                                      
   Tooth                                              (8)          (9)          (10)                                                
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 CARDIOVASCULAR SYSTEM                                                                                                              
                                                                                                                                    
   Heart                                              (55)         (38)         (55)                                                
      Schwannoma NOS                                                             1 (2%)                                             
      Atrium, Histiocytic Sarcoma, Metastatic                       1 (3%)                                                          
      Atrium Right, Liposarcoma, Metastatic, Skin                   1 (3%)                                                          
      Endocardium, Schwannoma NOS                      2 (4%)                                                                       
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 ENDOCRINE SYSTEM                                                                                                                   
                                                                                                                                    
   Adrenal Gland, Cortex                              (54)         (37)         (54)                                                
      Histiocytic Sarcoma, Metastatic                  1 (2%)                                                                       
   Adrenal Gland, Medulla                             (55)         (48)         (55)                                                
      Pheochromocytoma Malignant                       1 (2%)       2 (4%)       3 (5%)                                             
      Pheochromocytoma Benign                          9 (16%)     14 (29%)     13 (24%)                                            
      Bilateral, Pheochromocytoma Benign               4 (7%)       3 (6%)       6 (11%)                                            
   Islets, Pancreatic                                 (54)         (36)         (54)                                                
      Adenoma                                          1 (2%)       1 (3%)                                                          
   Parathyroid Gland                                  (54)         (36)         (54)                                                
   Pituitary Gland                                    (54)         (54)         (54)                                                
      Pars Distalis, Adenoma                          13 (24%)      9 (17%)      5 (9%)                                             
      Pars Distalis, Carcinoma                                      1 (2%)                                                          
   Thyroid Gland                                      (55)         (38)         (55)                                                
      Histiocytic Sarcoma, Metastatic                  1 (2%)                                                                       
      C-Cell, Adenoma                                  5 (9%)       2 (5%)       3 (5%)                                             
      C-Cell, Carcinoma                                2 (4%)       2 (5%)       3 (5%)                                             
      Follicular Cell, Adenocarcinoma                  2 (4%)                                                                       
      Follicular Cell, Adenoma                         1 (2%)                    1 (2%)                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENERAL BODY SYSTEM                                                                                                                
                                                                                                                                    
   None                                                                                                                             
____________________________________________________________________________________________________________________________________
                                                                                                                                    
                                                             Page   8                                                               
NTP Experiment-Test: 05040-01  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 09/05/94  
Route: GAVAGE                                                                                                     Time: 10:19:35  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS MALE                     VEHICLE      25 MG/KG     50 MG/KG                                               
                                                   CONTROL                                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 GENITAL SYSTEM                                                                                                                     
                                                                                                                                    
   Coagulating Gland                                               (1)          (2)                                                 
   Epididymis                                         (53)         (37)         (55)                                                
      Histiocytic Sarcoma, Metastatic                  1 (2%)                                                                       
   Penis                                                           (1)                                                              
   Preputial Gland                                    (53)         (34)         (54)                                                
      Adenoma                                         11 (21%)      8 (24%)      7 (13%)                                            
      Carcinoma                                        1 (2%)       1 (3%)       3 (6%)                                             
      Histiocytic Sarcoma, Metastatic                  1 (2%)                                                                       
   Prostate                                           (53)         (41)         (55)                                                
      Adenoma                                                       1 (2%)                                                          
      Serosa, Histiocytic Sarcoma, Metastatic          1 (2%)                                                                       
   Seminal Vesicle                                    (53)         (36)         (55)                                                
      Serosa, Histiocytic Sarcoma, Metastatic          1 (2%)                                                                       
   Testes                                             (54)         (54)         (55)                                                
      Bilateral, Interstitial Cell, Adenoma           37 (69%)     36 (67%)     43 (78%)                                            
      Interstitial Cell, Adenoma                       9 (17%)     13 (24%)      6 (11%)                                            
      Tunic, Histiocytic Sarcoma, Metastatic           1 (2%)                                                                       
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 HEMATOPOIETIC SYSTEM                                                                                                               
                                                                                                                                    
   Blood                                              (22)         (25)         (29)                                                
      Histiocytic Sarcoma, Metastatic                  1 (5%)                                                                       
   Bone Marrow                                        (55)         (37)         (55)                                                
      Histiocytic Sarcoma, Metastatic                  1 (2%)                                                                       
   Lymph Node                                         (55)         (41)         (55)                                                
      Mediastinal, Histiocytic Sarcoma, Metastatic                  1 (2%)                                                          
   Lymph Node, Mandibular                             (52)         (38)         (54)                                                
   Lymph Node, Mesenteric                             (53)         (38)         (54)                                                
      Inguinal, Lumbar, Mediastinal, Histiocytic                                                                                    
          Sarcoma, Metastatic                          1 (2%)                                                                       
      Mediastinal, Mandibular, Histiocytic Sarcoma,                                                                                 
           Metastatic                                  1 (2%)                                                                       
   Spleen                                             (55)         (52)         (55)                                                
      Histiocytic Sarcoma, Metastatic                  1 (2%)                                                                       
      Leiomyosarcoma, Metastatic, Intestine Small                   1 (2%)                                                          
      Capsule, Histiocytic Sarcoma, Metastatic         1 (2%)                                                                       
   Thymus                                             (46)         (35)         (46)                                                
      Histiocytic Sarcoma, Metastatic                  1 (2%)                                                                       
____________________________________________________________________________________________________________________________________
                                                                                                                                    
                                                             Page   9                                                               
NTP Experiment-Test: 05040-01  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 09/05/94  
Route: GAVAGE                                                                                                     Time: 10:19:35  
____________________________________________________________________________________________________________________________________
                                                                                                                                    
         FISCHER 344 RATS MALE                     VEHICLE      25 MG/KG     50 MG/KG                                               
                                                   CONTROL                                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 INTEGUMENTARY SYSTEM                                                                                                               
                                                                                                                                    
   Mammary Gland                                      (49)         (29)         (53)                                                
      Adenocarcinoma                                   1 (2%)                                                                       
      Adenoma                                          1 (2%)                                                                       
      Fibroadenoma                                     3 (6%)                                                                       
      Histiocytic Sarcoma, Metastatic                  1 (2%)                                                                       
   Skin                                               (55)         (37)         (54)                                                
      Basal Cell Adenoma                                                         2 (4%)                                             
      Basosquamous Tumor Malignant                                  1 (3%)                                                          
      Keratoacanthoma                                  2 (4%)                    2 (4%)                                             
      Subcutaneous Tissue, Fibroma                     1 (2%)       1 (3%)                                                          
      Subcutaneous Tissue, Fibrosarcoma                1 (2%)       1 (3%)                                                          
      Subcutaneous Tissue, Histiocytic Sarcoma         2 (4%)       1 (3%)                                                          
      Subcutaneous Tissue, Lipoma                                   1 (3%)                                                          
      Subcutaneous Tissue, Liposarcoma                              1 (3%)                                                          
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 MUSCULOSKELETAL SYSTEM                                                                                                             
                                                                                                                                    
   Bone                                               (55)         (37)         (55)                                                
      Rib, Osteosarcoma                                                          1 (2%)                                             
   Skeletal Muscle                                    (4)          (3)          (6)                                                 
      Histiocytic Sarcoma, Metastatic                  1 (25%)                                                                      
      Leiomyosarcoma, Metastatic, Intestine Small                   1 (33%)                                                         
      Osteosarcoma, Extension, Metastatic, Bone                                  1 (17%)                                            
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 NERVOUS SYSTEM                                                                                                                     
                                                                                                                                    
   Brain                                              (55)         (37)         (55)                                                
      Meninges, Cerebrum, Histiocytic Sarcoma,                                                                                      
           Metastatic                                               1 (3%)                                                          
   Spinal Cord                                        (13)         (13)         (9)                                                 
____________________________________________________________________________________________________________________________________
                                                                                                                                    
 RESPIRATORY SYSTEM                                                                                                                 
                                                                                                                                    
   Lung                                               (55)         (38)         (55)                                                
      Alveolar/Bronchiolar Adenoma                     1 (2%)                                                                       
      Carcinoma, Metastatic, Zymbal's Gland                         1 (3%)                                                          
      Histiocytic Sarcoma                                                        1 (2%)                                             
      Histiocytic Sarcoma, Metastatic                  2 (4%)       1 (3%)                                                          
      Liposarcoma, Metastatic, Skin                                 1 (3%)                                                          
      Osteosarcoma, Metastatic, Bone                                             1 (2%)                                             
      Pheochromocytoma Malignant, Metastatic,                                                                                       
          Adrenal Gland                                                          1 (2%)                                             
   Nose                                               (55)         (37)         (55)                                                
                                                             Page  10                                                               
NTP Experiment-Test: 05040-01  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 09/05/94  
Route: GAVAGE                                                                                                     Time: 10:19:35  
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         FISCHER 344 RATS MALE                     VEHICLE      25 MG/KG     50 MG/KG                                               
                                                   CONTROL                                                                          
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RESPIRATORY SYSTEM - cont                                                                                                           
   Trachea                                            (53)         (37)         (55)                                                
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 SPECIAL SENSES SYSTEM                                                                                                              
                                                                                                                                    
   Ear                                                (2)          (2)                                                              
      Canal, Carcinoma, Extension, Metastatic,                                                                                      
           Zymbal's Gland                              1 (50%)                                                                      
   Eye                                                (2)          (3)          (4)                                                 
   Harderian Gland                                    (2)          (2)          (3)                                                 
   Zymbal's Gland                                     (3)          (4)          (1)                                                 
      Adenoma                                                       1 (25%)                                                         
      Carcinoma                                        1 (33%)      3 (75%)      1 (100%)                                           
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 URINARY SYSTEM                                                                                                                     
                                                                                                                                    
   Kidney                                             (55)         (55)         (55)                                                
      Histiocytic Sarcoma                                                        1 (2%)                                             
      Capsule, Histiocytic Sarcoma, Metastatic         1 (2%)                                                                       
      Renal Tubule, Adenoma                                         4 (7%)       8 (15%)                                            
   Urinary Bladder                                    (51)         (37)         (55)                                                
      Serosa, Histiocytic Sarcoma, Metastatic          1 (2%)                                                                       
      Transitional Epithelium, Carcinoma, Papillary                 1 (3%)                                                          
                                                                                                                                    
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 SYSTEMIC LESIONS                                                                                                                   
   Multiple Organs                                   *(55)        *(55)        *(55)                                                
      Histiocytic Sarcoma                              2 (4%)       1 (2%)       1 (2%)                                             
      Leukemia Mononuclear                            28 (51%)     26 (47%)     31 (56%)                                            
      Mesothelioma Malignant                           1 (2%)       3 (5%)       1 (2%)                                             
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     *   Number of animals with any tissue examined microscopically                                                                 
                                                             Page  11                                                               
NTP Experiment-Test: 05040-01  INCIDENCE RATES OF NEOPLASMS BY ANATOMIC SITE (SYSTEMIC LESIONS ABRIDGED) (a)      Report: PEIRPT05
Study Type: CHRONIC                                            HYDROQUINONE                                       Date: 09/05/94  
Route: GAVAGE                                                                                                     Time: 10:19:35  
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         FISCHER 344 RATS MALE                     VEHICLE      25 MG/KG     50 MG/KG                                               
                                                   CONTROL                                                                          
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TUMOR SUMMARY                                                                                                                       
                                                                                                                                    
   Total Animals with Primary Neoplasms (b)            53          53          54                                                   
     Total Primary Neoplasms                          145         140         143                                                   
                                                                                                                                    
   Total Animals with Benign Neoplasms                 50          50          52                                                   
     Total Benign Neoplasms                           102          96          98                                                   
                                                                                                                                    
   Total Animals with Malignant Neoplasms              35          37          38                                                   
     Total Malignant Neoplasms                         41          44          44                                                   
                                                                                                                                    
   Total Animals with Metastatic Neoplasms              5           6           2                                                   
     Total Metastatic Neoplasm                         37          34           3                                                   
                                                                                                                                    
   Total Animals with Malignant Neoplasms                                                                                           
   Uncertain Primary Site                                                                                                           
                                                                                                                                    
   Total Animals with Neoplasms Uncertain-                                                                                          
   Benign or Malignant                                  2                       1                                                   
     Total Uncertain Neoplasms                          2                       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                                                                              
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