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TDMS Study 88035-05 Pathology Tables

NTP                                        STATISTICAL ANALYSIS OF PRIMARY TUMORS                              REPORT: PEIRPT08     
LAB: Battelle Columbus                                         PRIMACLONE                                      DATE: 12/27/96       
EXPERIMENT: 88035 TEST: 05                                                                                     TIME: 13:17:01       
TEST TYPE:  CHRONIC                             CAGES FROM 0000 TO LAST CAGE                                   PAGE:       1        
CONT: N01-ES-05295                              ROUTE: DOSED FEED                                              NTP C#: C88035       
PATHOLOGIST: TOFT, J.                                                                                          CAS: 0000125-33-7    
------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    

               REASONS FOR REMOVAL:    ALL                                                                                          
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
               REMOVAL DATE RANGE:     ALL                                                                                          
                                                                                                                                    
               TREATMENT GROUPS:       MERGE   001   001                        0 PPM                                               
                                       MERGE   002   002                        0 PPM                                               
                                       MERGE   003   003                        600 PPM                                             
                                       MERGE   004   004                        600 PPM                                             
                                       MERGE   005   005                        1300 PPM                                            
                                       MERGE   006   006                        1300 PPM                                            
                                       MERGE   007   007                        2500 PPM                                            
                                       MERGE   008   008                        2500 PPM                                            
NTP                                        STATISTICAL ANALYSIS OF PRIMARY TUMORS                              REPORT: PEIRPT08     
LAB: Battelle Columbus                                         PRIMACLONE                                      DATE: 12/27/96       
EXPERIMENT: 88035 TEST: 05                                                                                     TIME: 13:17:01       
TEST TYPE:  CHRONIC                             CAGES FROM 0000 TO LAST CAGE                                                        
CONT: N01-ES-05295                              ROUTE: DOSED FEED                                              NTP C#: C88035       
PATHOLOGIST: TOFT, J.                                                                                          CAS: 0000125-33-7    




                                                    RATS(FISCHER344)
                                              ----------------------------
             FOR ALL DOSES THE TUMOR RATES IN THE FOLLOWING TISSUES/ORGANS ARE BASED ON NUMBER OF TISSUES EXAMINED.
             IN OTHER TISSUES/ORGANS, RATES ARE BASED ON NUMBER OF ANIMALS NECROPSIED.
                                                                    

                                                    ----------------

                                                    Adrenal Cortex
                                                    Adrenal Medulla
                                                    Bone Marrow
                                                    Brain
                                                    Clitoral Gland
                                                    Clitoral/Preputial Gland
                                                    Epididymis
                                                    Heart
                                                    Islets, Pancreatic
                                                    Kidney
                                                    Liver
                                                    Lung
                                                    Nose
                                                    Ovary
                                                    Pancreas
                                                    Parathyroid Gland
                                                    Pituitary Gland
                                                    Preputial Gland
                                                    Prostate
                                                    Salivary Glands
                                                    Spleen
                                                    Testes
                                                    Thymus
                                                    Thyroid Gland
                                                    Urinary Bladder
NTP                                        STATISTICAL ANALYSIS OF PRIMARY TUMORS                              REPORT: PEIRPT08     
LAB: Battelle Columbus                                         PRIMACLONE                                      DATE: 12/27/96       
EXPERIMENT: 88035 TEST: 05                                                                                     TIME: 13:17:01       
TEST TYPE:  CHRONIC                             CAGES FROM 0000 TO LAST CAGE                                                        
CONT: N01-ES-05295                              ROUTE: DOSED FEED                                              NTP C#: C88035       
PATHOLOGIST: TOFT, J.                                                                                          CAS: 0000125-33-7    




                                     SUMMARY OF STATISTICALLY SIGNIFICANT (P<=.05) RESULTS
                                         IN THE ANALYSIS OF THE STUDY OF 3-7PRIMACLONE

              ====================================================================================================

                                                           MALE RATS
                                                          -------------
                  ORGAN                               MORPHOLOGY
                 -------                             ------------

              Adrenal Medulla               Pheochromocytoma Benign
                                            Pheochromocytoma: Benign, Complex, Malignant, NOS
              Brain                         Astrocytoma Malignant
              Mammary Gland                 Fibroma, Fibroadenoma, Carcinoma, or Adenoma
              Pituitary Gland: Pars Distalis or Unspecified Site
                                            Adenoma
                                            Carcinoma or Adenoma
              Skin                          Fibroma
                                            Fibroma, Fibrosarcoma, Sarcoma, Myxoma, Myxosarcoma, or Fibrous Histiocytoma
              Spleen                        Fibrosarcoma
              Testes                        Adenoma
              Thyroid Gland: C-Cell         Adenoma
                                            Carcinoma or Adenoma
              Thyroid Gland: Follicular Cell
                                            Adenoma
                                            Carcinoma or Adenoma
              All Organs                    Leukemia: Lymphocytic, Monocytic, Mononuclear, or Undifferentiated
                                            Benign Tumors
                                            Malignant Tumors
                                            Malignant and Benign Tumors

              ====================================================================================================
NTP                                        STATISTICAL ANALYSIS OF PRIMARY TUMORS                              REPORT: PEIRPT08     
LAB: Battelle Columbus                                         PRIMACLONE                                      DATE: 12/27/96       
EXPERIMENT: 88035 TEST: 05                                                                                     TIME: 13:17:01       
TEST TYPE:  CHRONIC                             CAGES FROM 0000 TO LAST CAGE                                                        
CONT: N01-ES-05295                              ROUTE: DOSED FEED                                              NTP C#: C88035       
PATHOLOGIST: TOFT, J.                                                                                          CAS: 0000125-33-7    




                                     SUMMARY OF STATISTICALLY SIGNIFICANT (P<=.05) RESULTS
                                         IN THE ANALYSIS OF THE STUDY OF 3-7PRIMACLONE

              ====================================================================================================

                                                           FEMALE RATS
                                                          -------------
                  ORGAN                               MORPHOLOGY
                 -------                             ------------

              Mammary Gland                 Fibroadenoma
                                            Fibroma, Fibroadenoma or Adenoma
                                            Fibroma, Fibroadenoma, Carcinoma, or Adenoma
              Oral Cavity (Oral Mucosa, Tongue, Pharynx, Tooth, Gingiva)
                                            Squamous Cell Carcinoma
                                            Squamous Cell Carcinoma, Papilloma Squamous, or Papilloma
              Oral Mucosa                   Squamous Cell Carcinoma
              All Organs                    Leukemia: Lymphocytic, Monocytic, Mononuclear, or Undifferentiated
                                            Malignant and Benign Tumors

              ====================================================================================================
         DATE: 12/27/96                     EXPERIMENT: 88035 TEST: 05                                                 PAGE   1
                              STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- 3-7PRIMACLONE

                                                 TERMINAL SACRIFICE AT 104 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   0 PPM        600 PPM      1300 PPM     2500 PPM  |   0 PPM        600 PPM      1300 PPM     2500 PPM  |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Adrenal Cortex                                                                                                                   |
|     Adenoma                                                                                                                     |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  0/50 (0%)    0/50 (0%)    0/50 (0%)    0/50 (0%)  |  1/50 (2%)    2/50 (4%)    0/50 (0%)    1/50 (2%)  |
|ADJUSTED (b)           |   0.0%         0.0%         0.0%         0.0%      |   4.2%         7.4%         0.0%         3.6%      |
|TERMINAL (d)           |  0/13 (0%)    0/7 (0%)     0/4 (0%)     0/0        |  1/24 (4%)    2/27 (7%)    0/31 (0%)    1/28 (4%)  |
|FIRST INCIDENCE (DAYS) |   ---          ---          ---          ---       |   722 (T)      722 (T)      ---          722 (T)   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |    (e)          (e)          (e)          (e)      |  P=0.434N     P=0.541      P=0.449N     P=0.728N   |
|INCIDENTAL TUMOR       |    (e)          (e)          (e)          (e)      |  P=0.434N     P=0.541      P=0.449N     P=0.728N   |
|LOGISTIC REGRESSION    |    (e)          (e)          (e)          (e)      |  P=0.434N     P=0.541      P=0.449N     P=0.728N   |
|COCHRAN-ARMITAGE       |    (e)                                             |  P=0.478N                                          |
|FISHER EXACT           |                 (e)          (e)          (e)      |               P=0.500      P=0.500N     P=0.753N   |
|=================================================================================================================================|
|                                                                                                                                 |
|Adrenal Medulla                                                                                                                  |
|     Pheochromocytoma Benign                                                                                                     |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            | 23/50 (46%)  28/50 (56%)  24/50 (48%)  12/49 (24%) |  2/50 (4%)    0/50 (0%)    2/49 (4%)    3/50 (6%)  |
|ADJUSTED (b)           |  79.6%        83.3%        87.0%        85.0%      |   6.8%         0.0%         5.2%        10.7%      |
|TERMINAL (d)           |  8/13 (62%)   3/7 (43%)    2/4 (50%)    0/0        |  1/24 (4%)    0/27 (0%)    1/31 (3%)    3/28 (11%) |
|FIRST INCIDENCE (DAYS) |   305          562          529          522       |   660          ---          389          722 (T)   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P<0.001 **   P=0.066      P=0.017 *    P<0.001 ** |  P=0.263      P=0.236N     P=0.635N     P=0.559    |
|INCIDENTAL TUMOR       |  P=0.170N     P=0.175      P=0.392      P=0.627N   |  P=0.243      P=0.291N     P=0.691N     P=0.523    |
|LOGISTIC REGRESSION    |  P=0.231N     P=0.213      P=0.413      P=0.367N   |  P=0.226      P=0.251N     P=0.666      P=0.519    |
|COCHRAN-ARMITAGE       |  P=0.006N**                                        |  P=0.228                                           |
|FISHER EXACT           |               P=0.212      P=0.500      P=0.021N*  |               P=0.247N     P=0.684      P=0.500    |
|=================================================================================================================================|
         DATE: 12/27/96                     EXPERIMENT: 88035 TEST: 05                                                 PAGE   2
                              STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- 3-7PRIMACLONE

                                                 TERMINAL SACRIFICE AT 104 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   0 PPM        600 PPM      1300 PPM     2500 PPM  |   0 PPM        600 PPM      1300 PPM     2500 PPM  |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Adrenal Medulla                                                                                                                  |
|     Pheochromocytoma: Benign, Complex, Malignant, NOS                                                                           |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            | 23/50 (46%)  28/50 (56%)  24/50 (48%)  12/49 (24%) |  2/50 (4%)    0/50 (0%)    2/49 (4%)    3/50 (6%)  |
|ADJUSTED (b)           |  79.6%        83.3%        87.0%        85.0%      |   6.8%         0.0%         5.2%        10.7%      |
|TERMINAL (d)           |  8/13 (62%)   3/7 (43%)    2/4 (50%)    0/0        |  1/24 (4%)    0/27 (0%)    1/31 (3%)    3/28 (11%) |
|FIRST INCIDENCE (DAYS) |   305          562          529          522       |   660          ---          389          722 (T)   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P<0.001 **   P=0.066      P=0.017 *    P<0.001 ** |  P=0.263      P=0.236N     P=0.635N     P=0.559    |
|INCIDENTAL TUMOR       |  P=0.170N     P=0.175      P=0.392      P=0.627N   |  P=0.243      P=0.291N     P=0.691N     P=0.523    |
|LOGISTIC REGRESSION    |  P=0.231N     P=0.213      P=0.413      P=0.367N   |  P=0.226      P=0.251N     P=0.666      P=0.519    |
|COCHRAN-ARMITAGE       |  P=0.006N**                                        |  P=0.228                                           |
|FISHER EXACT           |               P=0.212      P=0.500      P=0.021N*  |               P=0.247N     P=0.684      P=0.500    |
|=================================================================================================================================|
|                                                                                                                                 |
|Brain                                                                                                                            |
|     Astrocytoma Malignant                                                                                                       |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  0/50 (0%)    0/50 (0%)    0/49 (0%)    2/49 (4%)  |  1/50 (2%)    0/50 (0%)    1/50 (2%)    0/50 (0%)  |
|ADJUSTED (b)           |   0.0%         0.0%         0.0%        21.3%      |   2.1%         0.0%         3.2%         0.0%      |
|TERMINAL (d)           |  0/13 (0%)    0/7 (0%)     0/4 (0%)     0/0        |  0/24 (0%)    0/27 (0%)    1/31 (3%)    0/28 (0%)  |
|FIRST INCIDENCE (DAYS) |   ---          ---          ---          589       |   536          ---          722 (T)      ---       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.004 **     (e)          (e)        P=0.039 *  |  P=0.395N     P=0.527N     P=0.735N     P=0.508N   |
|INCIDENTAL TUMOR       |  P=0.143        (e)          (e)        P=0.524    |  P=0.401N     P=0.362N     P=0.732N     P=0.455N   |
|LOGISTIC REGRESSION    |  P=0.048 *      (e)          (e)        P=0.196    |  P=0.420N     P=0.420N     P=0.749      P=0.522N   |
|COCHRAN-ARMITAGE       |  P=0.045 *                                         |  P=0.409N                                          |
|FISHER EXACT           |                 (e)          (e)        P=0.242    |               P=0.500N     P=0.753N     P=0.500N   |
|=================================================================================================================================|
         DATE: 12/27/96                     EXPERIMENT: 88035 TEST: 05                                                 PAGE   3
                              STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- 3-7PRIMACLONE

                                                 TERMINAL SACRIFICE AT 104 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   0 PPM        600 PPM      1300 PPM     2500 PPM  |   0 PPM        600 PPM      1300 PPM     2500 PPM  |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Clitoral/Preputial Gland                                                                                                         |
|     Adenoma                                                                                                                     |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  2/50 (4%)    1/50 (2%)    2/50 (4%)    0/49 (0%)  |  4/49 (8%)    1/49 (2%)    4/50 (8%)    1/50 (2%)  |
|ADJUSTED (b)           |  10.8%         4.5%         8.0%         0.0%      |  14.9%         3.7%        10.7%         2.5%      |
|TERMINAL (d)           |  1/13 (8%)    0/7 (0%)     0/4 (0%)     0/0        |  3/24 (13%)   1/27 (4%)    2/31 (6%)    0/28 (0%)  |
|FIRST INCIDENCE (DAYS) |   655          673          613          ---       |   660          722 (T)      501          605       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.575      P=0.592N     P=0.522      P=0.996N   |  P=0.196N     P=0.157N     P=0.529N     P=0.160N   |
|INCIDENTAL TUMOR       |  P=0.485N     P=0.548N     P=0.672      P=0.983N   |  P=0.221N     P=0.192N     P=0.585N     P=0.183N   |
|LOGISTIC REGRESSION    |  P=0.405N     P=0.514N     P=0.663      P=0.748N   |  P=0.221N     P=0.199N     P=0.631N     P=0.175N   |
|COCHRAN-ARMITAGE       |  P=0.208N                                          |  P=0.224N                                          |
|FISHER EXACT           |               P=0.500N     P=0.691N     P=0.253N   |               P=0.181N     P=0.631N     P=0.175N   |
|=================================================================================================================================|
|                                                                                                                                 |
|Clitoral/Preputial Gland                                                                                                         |
|     Carcinoma                                                                                                                   |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  1/50 (2%)    0/50 (0%)    0/50 (0%)    0/49 (0%)  |  1/49 (2%)    0/49 (0%)    1/50 (2%)    2/50 (4%)  |
|ADJUSTED (b)           |   2.3%         0.0%         0.0%         0.0%      |   3.4%         0.0%         2.0%         6.3%      |
|TERMINAL (d)           |  0/13 (0%)    0/7 (0%)     0/4 (0%)     0/0        |  0/24 (0%)    0/27 (0%)    0/31 (0%)    1/28 (4%)  |
|FIRST INCIDENCE (DAYS) |   526          ---          ---          ---       |   702          ---          456          675       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.298N     P=0.491N     P=0.483N     P=0.509N   |  P=0.269      P=0.507N     P=0.740N     P=0.543    |
|INCIDENTAL TUMOR       |  P=0.191N     P=0.464N     P=0.682N     P=0.295N   |  P=0.229      P=0.654N     P=0.755      P=0.432    |
|LOGISTIC REGRESSION    |  P=0.254N     P=0.552N     P=0.545N     P=0.436N   |  P=0.236      P=0.517N     P=0.753      P=0.506    |
|COCHRAN-ARMITAGE       |  P=0.297N                                          |  P=0.246                                           |
|FISHER EXACT           |               P=0.500N     P=0.500N     P=0.505N   |               P=0.500N     P=0.747N     P=0.508    |
|=================================================================================================================================|
         DATE: 12/27/96                     EXPERIMENT: 88035 TEST: 05                                                 PAGE   4
                              STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- 3-7PRIMACLONE

                                                 TERMINAL SACRIFICE AT 104 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   0 PPM        600 PPM      1300 PPM     2500 PPM  |   0 PPM        600 PPM      1300 PPM     2500 PPM  |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Clitoral/Preputial Gland                                                                                                         |
|     Carcinoma or Adenoma                                                                                                        |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  3/50 (6%)    1/50 (2%)    2/50 (4%)    0/49 (0%)  |  5/49 (10%)   1/49 (2%)    5/50 (10%)   3/50 (6%)  |
|ADJUSTED (b)           |  12.8%         4.5%         8.0%         0.0%      |  17.9%         3.7%        12.6%         8.7%      |
|TERMINAL (d)           |  1/13 (8%)    0/7 (0%)     0/4 (0%)     0/0        |  3/24 (13%)   1/27 (4%)    2/31 (6%)    1/28 (4%)  |
|FIRST INCIDENCE (DAYS) |   526          673          613          ---       |   660          722 (T)      456          605       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.468N     P=0.376N     P=0.653N     P=0.484N   |  P=0.417N     P=0.093N     P=0.514N     P=0.309N   |
|INCIDENTAL TUMOR       |  P=0.186N     P=0.326N     P=0.613N     P=0.280N   |  P=0.472N     P=0.141N     P=0.583N     P=0.398N   |
|LOGISTIC REGRESSION    |  P=0.134N     P=0.304N     P=0.501N     P=0.156N   |  P=0.464N     P=0.118N     P=0.630      P=0.349N   |
|COCHRAN-ARMITAGE       |  P=0.109N                                          |  P=0.463N                                          |
|FISHER EXACT           |               P=0.309N     P=0.500N     P=0.125N   |               P=0.102N     P=0.617N     P=0.346N   |
|=================================================================================================================================|
|                                                                                                                                 |
|Islets, Pancreatic                                                                                                               |
|     Carcinoma or Adenoma                                                                                                        |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  2/50 (4%)    0/50 (0%)    0/50 (0%)    0/49 (0%)  |  0/50 (0%)    0/50 (0%)    1/50 (2%)    0/50 (0%)  |
|ADJUSTED (b)           |  11.9%         0.0%         0.0%         0.0%      |   0.0%         0.0%         3.2%         0.0%      |
|TERMINAL (d)           |  1/13 (8%)    0/7 (0%)     0/4 (0%)     0/0        |  0/24 (0%)    0/27 (0%)    1/31 (3%)    0/28 (0%)  |
|FIRST INCIDENCE (DAYS) |   683          ---          ---          ---       |   ---          ---          722 (T)      ---       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.333N     P=0.325N     P=0.445N       (e)      |  P=0.689        (e)        P=0.551        (e)      |
|INCIDENTAL TUMOR       |  P=0.276N     P=0.294N     P=0.367N     P=0.983N   |  P=0.689        (e)        P=0.551        (e)      |
|LOGISTIC REGRESSION    |  P=0.257N     P=0.269N     P=0.376N     P=0.921N   |  P=0.689        (e)        P=0.551        (e)      |
|COCHRAN-ARMITAGE       |  P=0.112N                                          |  P=0.667                                           |
|FISHER EXACT           |               P=0.247N     P=0.247N     P=0.253N   |                 (e)        P=0.500        (e)      |
|=================================================================================================================================|
         DATE: 12/27/96                     EXPERIMENT: 88035 TEST: 05                                                 PAGE   5
                              STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- 3-7PRIMACLONE

                                                 TERMINAL SACRIFICE AT 104 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   0 PPM        600 PPM      1300 PPM     2500 PPM  |   0 PPM        600 PPM      1300 PPM     2500 PPM  |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Kidney: Renal Tubule                                                                                                             |
|     Adenoma                                                                                                                     |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  2/50 (4%)    1/50 (2%)    1/50 (2%)    1/50 (2%)  |  0/50 (0%)    0/50 (0%)    0/50 (0%)    0/50 (0%)  |
|ADJUSTED (b)           |  10.3%         3.6%         2.9%         2.4%      |   0.0%         0.0%         0.0%         0.0%      |
|TERMINAL (d)           |  1/13 (8%)    0/7 (0%)     0/4 (0%)     0/0        |  0/24 (0%)    0/27 (0%)    0/31 (0%)    0/28 (0%)  |
|FIRST INCIDENCE (DAYS) |   619          654          613          529       |   ---          ---          ---          ---       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.424      P=0.572N     P=0.639N     P=0.589    |    (e)          (e)          (e)          (e)      |
|INCIDENTAL TUMOR       |  P=0.369N     P=0.520N     P=0.424N     P=0.494N   |    (e)          (e)          (e)          (e)      |
|LOGISTIC REGRESSION    |  P=0.435N     P=0.501N     P=0.513N     P=0.616N   |    (e)          (e)          (e)          (e)      |
|COCHRAN-ARMITAGE       |  P=0.404N                                          |    (e)                                             |
|FISHER EXACT           |               P=0.500N     P=0.500N     P=0.500N   |                 (e)          (e)          (e)      |
|=================================================================================================================================|
|                                                                                                                                 |
|Kidney: Renal Tubule                                                                                                             |
|     Carcinoma or Adenoma                                                                                                        |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  2/50 (4%)    1/50 (2%)    1/50 (2%)    2/50 (4%)  |  0/50 (0%)    0/50 (0%)    0/50 (0%)    0/50 (0%)  |
|ADJUSTED (b)           |  10.3%         3.6%         2.9%        16.3%      |   0.0%         0.0%         0.0%         0.0%      |
|TERMINAL (d)           |  1/13 (8%)    0/7 (0%)     0/4 (0%)     0/0        |  0/24 (0%)    0/27 (0%)    0/31 (0%)    0/28 (0%)  |
|FIRST INCIDENCE (DAYS) |   619          654          613          529       |   ---          ---          ---          ---       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.107      P=0.572N     P=0.639N     P=0.163    |    (e)          (e)          (e)          (e)      |
|INCIDENTAL TUMOR       |  P=0.573N     P=0.520N     P=0.424N     P=0.617N   |    (e)          (e)          (e)          (e)      |
|LOGISTIC REGRESSION    |  P=0.528      P=0.501N     P=0.513N     P=0.629    |    (e)          (e)          (e)          (e)      |
|COCHRAN-ARMITAGE       |  P=0.553                                           |    (e)                                             |
|FISHER EXACT           |               P=0.500N     P=0.500N     P=0.691N   |                 (e)          (e)          (e)      |
|=================================================================================================================================|
         DATE: 12/27/96                     EXPERIMENT: 88035 TEST: 05                                                 PAGE   6
                              STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- 3-7PRIMACLONE

                                                 TERMINAL SACRIFICE AT 104 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   0 PPM        600 PPM      1300 PPM     2500 PPM  |   0 PPM        600 PPM      1300 PPM     2500 PPM  |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Lung                                                                                                                             |
|     Alveolar/Bronchiolar Adenoma                                                                                                |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  1/50 (2%)    1/50 (2%)    0/50 (0%)    0/50 (0%)  |  0/49 (0%)    0/50 (0%)    1/50 (2%)    2/50 (4%)  |
|ADJUSTED (b)           |   2.6%         2.4%         0.0%         0.0%      |   0.0%         0.0%         2.5%         7.1%      |
|TERMINAL (d)           |  0/13 (0%)    0/7 (0%)     0/4 (0%)     0/0        |  0/24 (0%)    0/27 (0%)    0/31 (0%)    2/28 (7%)  |
|FIRST INCIDENCE (DAYS) |   583          583          ---          ---       |   ---          ---          668          722 (T)   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.277N     P=0.751N     P=0.490N     P=0.597N   |  P=0.077        (e)        P=0.532      P=0.272    |
|INCIDENTAL TUMOR       |  P=0.077N     P=0.688N     P=0.326N     P=0.258N   |  P=0.068        (e)        P=0.427      P=0.272    |
|LOGISTIC REGRESSION    |  P=0.183N     P=0.745      P=0.509N     P=0.474N   |  P=0.071        (e)        P=0.501      P=0.272    |
|COCHRAN-ARMITAGE       |  P=0.222N                                          |  P=0.068                                           |
|FISHER EXACT           |               P=0.753N     P=0.500N     P=0.500N   |                 (e)        P=0.505      P=0.253    |
|=================================================================================================================================|
|                                                                                                                                 |
|Lung                                                                                                                             |
|     Alveolar/Bronchiolar Carcinoma or Alveolar/Bronchiolar Adenoma                                                              |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  1/50 (2%)    1/50 (2%)    1/50 (2%)    1/50 (2%)  |  0/49 (0%)    0/50 (0%)    1/50 (2%)    2/50 (4%)  |
|ADJUSTED (b)           |   2.6%         2.4%         2.1%         5.6%      |   0.0%         0.0%         2.5%         7.1%      |
|TERMINAL (d)           |  0/13 (0%)    0/7 (0%)     0/4 (0%)     0/0        |  0/24 (0%)    0/27 (0%)    0/31 (0%)    2/28 (7%)  |
|FIRST INCIDENCE (DAYS) |   583          583          551          589       |   ---          ---          668          722 (T)   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.506      P=0.751N     P=0.745N     P=0.621    |  P=0.077        (e)        P=0.532      P=0.272    |
|INCIDENTAL TUMOR       |  P=0.274N     P=0.688N     P=0.555N     P=0.469N   |  P=0.068        (e)        P=0.427      P=0.272    |
|LOGISTIC REGRESSION    |  P=0.531N     P=0.745      P=0.749      P=0.755N   |  P=0.071        (e)        P=0.501      P=0.272    |
|COCHRAN-ARMITAGE       |  P=0.628                                           |  P=0.068                                           |
|FISHER EXACT           |               P=0.753N     P=0.753N     P=0.753N   |                 (e)        P=0.505      P=0.253    |
|=================================================================================================================================|
         DATE: 12/27/96                     EXPERIMENT: 88035 TEST: 05                                                 PAGE   7
                              STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- 3-7PRIMACLONE

                                                 TERMINAL SACRIFICE AT 104 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   0 PPM        600 PPM      1300 PPM     2500 PPM  |   0 PPM        600 PPM      1300 PPM     2500 PPM  |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Mammary Gland                                                                                                                    |
|     Adenoma                                                                                                                     |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |    #            #            #            #        |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  0/50 (0%)    1/50 (2%)    0/50 (0%)    0/50 (0%)  |  2/50 (4%)    0/50 (0%)    0/50 (0%)    0/50 (0%)  |
|ADJUSTED (b)           |   0.0%         2.4%         0.0%         0.0%      |   6.3%         0.0%         0.0%         0.0%      |
|TERMINAL (d)           |  0/13 (0%)    0/7 (0%)     0/4 (0%)     0/0        |  1/24 (4%)    0/27 (0%)    0/31 (0%)    0/28 (0%)  |
|FIRST INCIDENCE (DAYS) |   ---          583          ---          ---       |   566          ---          ---          ---       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.616N     P=0.510        (e)          (e)      |  P=0.104N     P=0.234N     P=0.212N     P=0.230N   |
|INCIDENTAL TUMOR       |  P=0.364N     P=0.567        (e)          (e)      |  P=0.114N     P=0.239N     P=0.253N     P=0.235N   |
|LOGISTIC REGRESSION    |  P=0.500N     P=0.481        (e)          (e)      |  P=0.113N     P=0.224N     P=0.248N     P=0.236N   |
|COCHRAN-ARMITAGE       |  P=0.543N                                          |  P=0.111N                                          |
|FISHER EXACT           |               P=0.500        (e)          (e)      |               P=0.247N     P=0.247N     P=0.247N   |
|=================================================================================================================================|
|                                                                                                                                 |
|Mammary Gland                                                                                                                    |
|     Carcinoma                                                                                                                   |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |    #            #            #            #        |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  2/50 (4%)    0/50 (0%)    0/50 (0%)    0/50 (0%)  |  1/50 (2%)    2/50 (4%)    1/50 (2%)    0/50 (0%)  |
|ADJUSTED (b)           |  12.8%         0.0%         0.0%         0.0%      |   3.4%         5.6%         2.0%         0.0%      |
|TERMINAL (d)           |  1/13 (8%)    0/7 (0%)     0/4 (0%)     0/0        |  0/24 (0%)    1/27 (4%)    0/31 (0%)    0/28 (0%)  |
|FIRST INCIDENCE (DAYS) |   704          ---          ---          ---       |   702          367          389          ---       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.388N     P=0.347N     P=0.532N       (e)      |  P=0.223N     P=0.514      P=0.741N     P=0.474N   |
|INCIDENTAL TUMOR       |  P=0.276N     P=0.294N     P=0.367N     P=0.983N   |  P=0.253N     P=0.522      P=0.720      P=0.573N   |
|LOGISTIC REGRESSION    |  P=0.321N     P=0.297N     P=0.450N     P=0.997N   |  P=0.284N     P=0.569      P=0.739      P=0.497N   |
|COCHRAN-ARMITAGE       |  P=0.111N                                          |  P=0.240N                                          |
|FISHER EXACT           |               P=0.247N     P=0.247N     P=0.247N   |               P=0.500      P=0.753N     P=0.500N   |
|=================================================================================================================================|
         DATE: 12/27/96                     EXPERIMENT: 88035 TEST: 05                                                 PAGE   8
                              STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- 3-7PRIMACLONE

                                                 TERMINAL SACRIFICE AT 104 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   0 PPM        600 PPM      1300 PPM     2500 PPM  |   0 PPM        600 PPM      1300 PPM     2500 PPM  |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Mammary Gland                                                                                                                    |
|     Carcinoma or Adenoma                                                                                                        |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |    #            #            #            #        |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  2/50 (4%)    1/50 (2%)    0/50 (0%)    0/50 (0%)  |  3/50 (6%)    2/50 (4%)    1/50 (2%)    0/50 (0%)  |
|ADJUSTED (b)           |  12.8%         2.4%         0.0%         0.0%      |   9.5%         5.6%         2.0%         0.0%      |
|TERMINAL (d)           |  1/13 (8%)    0/7 (0%)     0/4 (0%)     0/0        |  1/24 (4%)    1/27 (4%)    0/31 (0%)    0/28 (0%)  |
|FIRST INCIDENCE (DAYS) |   704          583          ---          ---       |   566          367          389          ---       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.307N     P=0.601N     P=0.532N       (e)      |  P=0.053N     P=0.485N     P=0.271N     P=0.111N   |
|INCIDENTAL TUMOR       |  P=0.124N     P=0.520N     P=0.367N     P=0.983N   |  P=0.064N     P=0.483N     P=0.353N     P=0.143N   |
|LOGISTIC REGRESSION    |  P=0.145N     P=0.503N     P=0.450N     P=0.997N   |  P=0.068N     P=0.438N     P=0.335N     P=0.120N   |
|COCHRAN-ARMITAGE       |  P=0.095N                                          |  P=0.059N                                          |
|FISHER EXACT           |               P=0.500N     P=0.247N     P=0.247N   |               P=0.500N     P=0.309N     P=0.121N   |
|=================================================================================================================================|
|                                                                                                                                 |
|Mammary Gland                                                                                                                    |
|     Fibroadenoma                                                                                                                |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |    #            #            #            #        |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  3/50 (6%)    3/50 (6%)    3/50 (6%)    0/50 (0%)  | 22/50 (44%)  25/50 (50%)  16/50 (32%)  12/50 (24%) |
|ADJUSTED (b)           |  13.8%        25.4%        35.8%         0.0%      |  61.7%        72.9%        40.9%        35.5%      |
|TERMINAL (d)           |  1/13 (8%)    1/7 (14%)    1/4 (25%)    0/0        | 11/24 (46%)  18/27 (67%)   9/31 (29%)   8/28 (29%) |
|FIRST INCIDENCE (DAYS) |   627          697          669          ---       |   415          578          550          489       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.296      P=0.530      P=0.339      P=0.878N   |  P=0.003N**   P=0.450      P=0.057N     P=0.017N*  |
|INCIDENTAL TUMOR       |  P=0.580N     P=0.618      P=0.549      P=0.248N   |  P=0.005N**   P=0.223      P=0.180N     P=0.029N*  |
|LOGISTIC REGRESSION    |  P=0.632N     P=0.634      P=0.537      P=0.373N   |  P=0.004N**   P=0.209      P=0.128N     P=0.028N*  |
|COCHRAN-ARMITAGE       |  P=0.093N                                          |  P=0.006N**                                        |
|FISHER EXACT           |               P=0.661N     P=0.661N     P=0.121N   |               P=0.344      P=0.151N     P=0.028N*  |
|=================================================================================================================================|
         DATE: 12/27/96                     EXPERIMENT: 88035 TEST: 05                                                 PAGE   9
                              STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- 3-7PRIMACLONE

                                                 TERMINAL SACRIFICE AT 104 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   0 PPM        600 PPM      1300 PPM     2500 PPM  |   0 PPM        600 PPM      1300 PPM     2500 PPM  |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Mammary Gland                                                                                                                    |
|     Fibroma, Fibroadenoma or Adenoma                                                                                            |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |    #            #            #            #        |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  3/50 (6%)    4/50 (8%)    3/50 (6%)    0/50 (0%)  | 24/50 (48%)  25/50 (50%)  16/50 (32%)  12/50 (24%) |
|ADJUSTED (b)           |  13.8%        27.2%        35.8%         0.0%      |  65.4%        72.9%        40.9%        35.5%      |
|TERMINAL (d)           |  1/13 (8%)    1/7 (14%)    1/4 (25%)    0/0        | 12/24 (50%)  18/27 (67%)   9/31 (29%)   8/28 (29%) |
|FIRST INCIDENCE (DAYS) |   627          583          669          ---       |   415          578          550          489       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.396      P=0.379      P=0.339      P=0.878N   |  P=0.001N**   P=0.548N     P=0.027N*    P=0.007N** |
|INCIDENTAL TUMOR       |  P=0.385N     P=0.481      P=0.549      P=0.248N   |  P=0.002N**   P=0.367      P=0.096N     P=0.011N*  |
|LOGISTIC REGRESSION    |  P=0.427N     P=0.492      P=0.537      P=0.373N   |  P=0.001N**   P=0.350      P=0.065N     P=0.011N*  |
|COCHRAN-ARMITAGE       |  P=0.076N                                          |  P=0.002N**                                        |
|FISHER EXACT           |               P=0.500      P=0.661N     P=0.121N   |               P=0.500      P=0.076N     P=0.011N*  |
|=================================================================================================================================|
|                                                                                                                                 |
|Mammary Gland                                                                                                                    |
|     Fibroma, Fibroadenoma, Carcinoma, or Adenoma                                                                                |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |    #            #            #            #        |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  5/50 (10%)   4/50 (8%)    3/50 (6%)    0/50 (0%)  | 25/50 (50%)  26/50 (52%)  17/50 (34%)  12/50 (24%) |
|ADJUSTED (b)           |  25.4%        27.2%        35.8%         0.0%      |  66.7%        73.4%        42.0%        35.5%      |
|TERMINAL (d)           |  2/13 (15%)   1/7 (14%)    1/4 (25%)    0/0        | 12/24 (50%)  18/27 (67%)   9/31 (29%)   8/28 (29%) |
|FIRST INCIDENCE (DAYS) |   627          583          669          ---       |   415          367          389          489       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.573      P=0.601      P=0.495      P=0.878N   |  P<0.001N**   P=0.546N     P=0.030N*    P=0.005N** |
|INCIDENTAL TUMOR       |  P=0.216N     P=0.553N     P=0.544N     P=0.236N   |  P=0.001N**   P=0.371      P=0.105N     P=0.007N** |
|LOGISTIC REGRESSION    |  P=0.261N     P=0.524N     P=0.576N     P=0.362N   |  P<0.001N**   P=0.372      P=0.074N     P=0.006N** |
|COCHRAN-ARMITAGE       |  P=0.022N*                                         |  P=0.001N**                                        |
|FISHER EXACT           |               P=0.500N     P=0.357N     P=0.028N*  |               P=0.500      P=0.078N     P=0.006N** |
|=================================================================================================================================|
         DATE: 12/27/96                     EXPERIMENT: 88035 TEST: 05                                                 PAGE  10
                              STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- 3-7PRIMACLONE

                                                 TERMINAL SACRIFICE AT 104 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   0 PPM        600 PPM      1300 PPM     2500 PPM  |   0 PPM        600 PPM      1300 PPM     2500 PPM  |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Oral Cavity (Oral Mucosa, Tongue, Pharynx, Tooth, Gingiva)                                                                       |
|     Squamous Cell Carcinoma                                                                                                     |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |    #            #            #            #        |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  1/50 (2%)    0/50 (0%)    0/50 (0%)    0/50 (0%)  |  0/50 (0%)    0/50 (0%)    0/50 (0%)    2/50 (4%)  |
|ADJUSTED (b)           |   2.1%         0.0%         0.0%         0.0%      |   0.0%         0.0%         0.0%         5.2%      |
|TERMINAL (d)           |  0/13 (0%)    0/7 (0%)     0/4 (0%)     0/0        |  0/24 (0%)    0/27 (0%)    0/31 (0%)    0/28 (0%)  |
|FIRST INCIDENCE (DAYS) |   463          ---          ---          ---       |   ---          ---          ---          433       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.300N     P=0.492N     P=0.496N     P=0.509N   |  P=0.056        (e)          (e)        P=0.273    |
|INCIDENTAL TUMOR       |  P=0.191N     P=0.464N     P=0.682N     P=0.295N   |  P=0.039 *      (e)          (e)        P=0.222    |
|LOGISTIC REGRESSION    |  P=0.253N     P=0.598N     P=0.602N     P=0.427N   |  P=0.032 *      (e)          (e)        P=0.225    |
|COCHRAN-ARMITAGE       |  P=0.295N                                          |  P=0.046 *                                         |
|FISHER EXACT           |               P=0.500N     P=0.500N     P=0.500N   |                 (e)          (e)        P=0.247    |
|=================================================================================================================================|
|                                                                                                                                 |
|Oral Cavity (Oral Mucosa, Tongue, Pharynx, Tooth, Gingiva)                                                                       |
|     Squamous Cell Carcinoma, Papilloma Squamous, or Papilloma                                                                   |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |    #            #            #            #        |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  1/50 (2%)    0/50 (0%)    1/50 (2%)    0/50 (0%)  |  0/50 (0%)    0/50 (0%)    0/50 (0%)    2/50 (4%)  |
|ADJUSTED (b)           |   2.1%         0.0%         5.3%         0.0%      |   0.0%         0.0%         0.0%         5.2%      |
|TERMINAL (d)           |  0/13 (0%)    0/7 (0%)     0/4 (0%)     0/0        |  0/24 (0%)    0/27 (0%)    0/31 (0%)    0/28 (0%)  |
|FIRST INCIDENCE (DAYS) |   463          ---          664          ---       |   ---          ---          ---          433       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.586N     P=0.492N     P=0.724      P=0.509N   |  P=0.056        (e)          (e)        P=0.273    |
|INCIDENTAL TUMOR       |  P=0.409N     P=0.464N     P=0.657      P=0.295N   |  P=0.039 *      (e)          (e)        P=0.222    |
|LOGISTIC REGRESSION    |  P=0.339N     P=0.598N     P=0.747      P=0.427N   |  P=0.032 *      (e)          (e)        P=0.225    |
|COCHRAN-ARMITAGE       |  P=0.409N                                          |  P=0.046 *                                         |
|FISHER EXACT           |               P=0.500N     P=0.753N     P=0.500N   |                 (e)          (e)        P=0.247    |
|=================================================================================================================================|
         DATE: 12/27/96                     EXPERIMENT: 88035 TEST: 05                                                 PAGE  11
                              STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- 3-7PRIMACLONE

                                                 TERMINAL SACRIFICE AT 104 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   0 PPM        600 PPM      1300 PPM     2500 PPM  |   0 PPM        600 PPM      1300 PPM     2500 PPM  |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Oral Mucosa                                                                                                                      |
|     Squamous Cell Carcinoma                                                                                                     |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |    #            #            #            #        |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  1/50 (2%)    0/50 (0%)    0/50 (0%)    0/50 (0%)  |  0/50 (0%)    0/50 (0%)    0/50 (0%)    2/50 (4%)  |
|ADJUSTED (b)           |   2.1%         0.0%         0.0%         0.0%      |   0.0%         0.0%         0.0%         5.2%      |
|TERMINAL (d)           |  0/13 (0%)    0/7 (0%)     0/4 (0%)     0/0        |  0/24 (0%)    0/27 (0%)    0/31 (0%)    0/28 (0%)  |
|FIRST INCIDENCE (DAYS) |   463          ---          ---          ---       |   ---          ---          ---          433       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.300N     P=0.492N     P=0.496N     P=0.509N   |  P=0.056        (e)          (e)        P=0.273    |
|INCIDENTAL TUMOR       |  P=0.191N     P=0.464N     P=0.682N     P=0.295N   |  P=0.039 *      (e)          (e)        P=0.222    |
|LOGISTIC REGRESSION    |  P=0.253N     P=0.598N     P=0.602N     P=0.427N   |  P=0.032 *      (e)          (e)        P=0.225    |
|COCHRAN-ARMITAGE       |  P=0.295N                                          |  P=0.046 *                                         |
|FISHER EXACT           |               P=0.500N     P=0.500N     P=0.500N   |                 (e)          (e)        P=0.247    |
|=================================================================================================================================|
|                                                                                                                                 |
|Pituitary Gland: Pars Distalis or Unspecified Site                                                                               |
|     Adenoma                                                                                                                     |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            | 17/49 (35%)  12/50 (24%)  11/48 (23%)   4/49 (8%)  | 16/49 (33%)  21/50 (42%)  14/49 (29%)  20/50 (40%) |
|ADJUSTED (b)           |  61.1%        37.7%        73.5%        22.9%      |  47.9%        56.7%        36.2%        54.5%      |
|TERMINAL (d)           |  5/13 (38%)   0/7 (0%)     2/4 (50%)    0/0        |  8/23 (35%)  12/27 (44%)   7/30 (23%)  12/28 (43%) |
|FIRST INCIDENCE (DAYS) |   281          526          437          436       |   541          410          543          491       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.318      P=0.391N     P=0.434      P=0.445    |  P=0.510N     P=0.281      P=0.223N     P=0.460    |
|INCIDENTAL TUMOR       |  P=0.005N**   P=0.141N     P=0.259N     P=0.012N*  |  P=0.380      P=0.195      P=0.456N     P=0.284    |
|LOGISTIC REGRESSION    |  P=0.003N**   P=0.172N     P=0.152N     P=0.003N** |  P=0.413      P=0.184      P=0.399N     P=0.289    |
|COCHRAN-ARMITAGE       |  P=0.001N**                                        |  P=0.389                                           |
|FISHER EXACT           |               P=0.172N     P=0.146N     P=0.001N** |               P=0.226      P=0.413N     P=0.291    |
|=================================================================================================================================|
         DATE: 12/27/96                     EXPERIMENT: 88035 TEST: 05                                                 PAGE  12
                              STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- 3-7PRIMACLONE

                                                 TERMINAL SACRIFICE AT 104 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   0 PPM        600 PPM      1300 PPM     2500 PPM  |   0 PPM        600 PPM      1300 PPM     2500 PPM  |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Pituitary Gland: Pars Distalis or Unspecified Site                                                                               |
|     Carcinoma or Adenoma                                                                                                        |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            | 17/49 (35%)  12/50 (24%)  11/48 (23%)   4/49 (8%)  | 16/49 (33%)  21/50 (42%)  14/49 (29%)  21/50 (42%) |
|ADJUSTED (b)           |  61.1%        37.7%        73.5%        22.9%      |  47.9%        56.7%        36.2%        56.0%      |
|TERMINAL (d)           |  5/13 (38%)   0/7 (0%)     2/4 (50%)    0/0        |  8/23 (35%)  12/27 (44%)   7/30 (23%)  12/28 (43%) |
|FIRST INCIDENCE (DAYS) |   281          526          437          436       |   541          410          543          491       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.318      P=0.391N     P=0.434      P=0.445    |  P=0.482      P=0.281      P=0.223N     P=0.394    |
|INCIDENTAL TUMOR       |  P=0.005N**   P=0.141N     P=0.259N     P=0.012N*  |  P=0.295      P=0.195      P=0.456N     P=0.208    |
|LOGISTIC REGRESSION    |  P=0.003N**   P=0.172N     P=0.152N     P=0.003N** |  P=0.330      P=0.184      P=0.399N     P=0.223    |
|COCHRAN-ARMITAGE       |  P=0.001N**                                        |  P=0.307                                           |
|FISHER EXACT           |               P=0.172N     P=0.146N     P=0.001N** |               P=0.226      P=0.413N     P=0.226    |
|=================================================================================================================================|
|                                                                                                                                 |
|Skin                                                                                                                             |
|     Basal Cell Carcinoma, Basal Cell Adenoma, Basosquamous Tumor (benign,                                                       |
|     malignant or NOS), or Trichoepithelioma                                                                                     |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |    #            #            #            #        |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  2/50 (4%)    1/50 (2%)    0/50 (0%)    1/50 (2%)  |  1/50 (2%)    0/50 (0%)    0/50 (0%)    0/50 (0%)  |
|ADJUSTED (b)           |  15.4%         7.7%         0.0%         2.8%      |   3.4%         0.0%         0.0%         0.0%      |
|TERMINAL (d)           |  2/13 (15%)   0/7 (0%)     0/4 (0%)     0/0        |  0/24 (0%)    0/27 (0%)    0/31 (0%)    0/28 (0%)  |
|FIRST INCIDENCE (DAYS) |   723 (T)      709          ---          544       |   702          ---          ---          ---       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.413      P=0.672N     P=0.520N     P=0.465    |  P=0.276N     P=0.500N     P=0.468N     P=0.474N   |
|INCIDENTAL TUMOR       |  P=0.631      P=0.631N     P=0.520N     P=0.705    |  P=0.335N     P=0.623N     P=0.573N     P=0.573N   |
|LOGISTIC REGRESSION    |  P=0.671      P=0.641N     P=0.520N     P=0.713    |  P=0.288N     P=0.513N     P=0.486N     P=0.497N   |
|COCHRAN-ARMITAGE       |  P=0.352N                                          |  P=0.295N                                          |
|FISHER EXACT           |               P=0.500N     P=0.247N     P=0.500N   |               P=0.500N     P=0.500N     P=0.500N   |
|=================================================================================================================================|
         DATE: 12/27/96                     EXPERIMENT: 88035 TEST: 05                                                 PAGE  13
                              STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- 3-7PRIMACLONE

                                                 TERMINAL SACRIFICE AT 104 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   0 PPM        600 PPM      1300 PPM     2500 PPM  |   0 PPM        600 PPM      1300 PPM     2500 PPM  |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Skin                                                                                                                             |
|     Basal or Sq. Cell Carcinoma, Carcinoma, Basosq. Tumor (M or B), Basal                                                       |
|     Cell Adenoma, Adenoma, Papilloma, Sq Papilloma, Keratoacanthoma, Trichoepithelioma                                          |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |    #            #            #            #        |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  3/50 (6%)    3/50 (6%)    1/50 (2%)    2/50 (4%)  |  1/50 (2%)    0/50 (0%)    1/50 (2%)    0/50 (0%)  |
|ADJUSTED (b)           |  23.1%        13.3%        14.3%         6.1%      |   3.4%         0.0%         3.2%         0.0%      |
|TERMINAL (d)           |  3/13 (23%)   0/7 (0%)     0/4 (0%)     0/0        |  0/24 (0%)    0/27 (0%)    1/31 (3%)    0/28 (0%)  |
|FIRST INCIDENCE (DAYS) |   723 (T)      562          697          544       |   702          ---          722 (T)      ---       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.158      P=0.496      P=0.716      P=0.182    |  P=0.379N     P=0.500N     P=0.714N     P=0.474N   |
|INCIDENTAL TUMOR       |  P=0.537      P=0.562      P=0.641N     P=0.506    |  P=0.422N     P=0.623N     P=0.751      P=0.573N   |
|LOGISTIC REGRESSION    |  P=0.605      P=0.645      P=0.704N     P=0.517    |  P=0.391N     P=0.513N     P=0.734N     P=0.497N   |
|COCHRAN-ARMITAGE       |  P=0.330N                                          |  P=0.409N                                          |
|FISHER EXACT           |               P=0.661N     P=0.309N     P=0.500N   |               P=0.500N     P=0.753N     P=0.500N   |
|=================================================================================================================================|
|                                                                                                                                 |
|Skin                                                                                                                             |
|     Fibroma                                                                                                                     |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |    #            #            #            #        |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  3/50 (6%)    3/50 (6%)    3/50 (6%)    0/50 (0%)  |  1/50 (2%)    1/50 (2%)    0/50 (0%)    1/50 (2%)  |
|ADJUSTED (b)           |   8.8%         8.8%        19.9%         0.0%      |   2.4%         3.7%         0.0%         3.6%      |
|TERMINAL (d)           |  0/13 (0%)    0/7 (0%)     0/4 (0%)     0/0        |  0/24 (0%)    1/27 (4%)    0/31 (0%)    1/28 (4%)  |
|FIRST INCIDENCE (DAYS) |   619          610          627          ---       |   634          722 (T)      ---          722 (T)   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.610      P=0.645      P=0.504      P=0.723N   |  P=0.580N     P=0.751      P=0.500N     P=0.758N   |
|INCIDENTAL TUMOR       |  P=0.011N*    P=0.521N     P=0.395N     P=0.040N*  |  P=0.586N     P=0.761N     P=0.581N     P=0.757N   |
|LOGISTIC REGRESSION    |  P=0.083N     P=0.661      P=0.655      P=0.163N   |  P=0.592N     P=0.754      P=0.512N     P=0.762    |
|COCHRAN-ARMITAGE       |  P=0.093N                                          |  P=0.599N                                          |
|FISHER EXACT           |               P=0.661N     P=0.661N     P=0.121N   |               P=0.753N     P=0.500N     P=0.753N   |
|=================================================================================================================================|
         DATE: 12/27/96                     EXPERIMENT: 88035 TEST: 05                                                 PAGE  14
                              STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- 3-7PRIMACLONE

                                                 TERMINAL SACRIFICE AT 104 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   0 PPM        600 PPM      1300 PPM     2500 PPM  |   0 PPM        600 PPM      1300 PPM     2500 PPM  |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Skin                                                                                                                             |
|     Fibroma, Fibrosarcoma, Sarcoma, Myxoma, Myxosarcoma, or Fibrous Histiocytoma                                                |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |    #            #            #            #        |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  3/50 (6%)    3/50 (6%)    5/50 (10%)   0/50 (0%)  |  3/50 (6%)    2/50 (4%)    1/50 (2%)    3/50 (6%)  |
|ADJUSTED (b)           |   8.8%         8.8%        24.7%         0.0%      |   7.0%         6.6%         2.2%        10.0%      |
|TERMINAL (d)           |  0/13 (0%)    0/7 (0%)     0/4 (0%)     0/0        |  0/24 (0%)    1/27 (4%)    0/31 (0%)    2/28 (7%)  |
|FIRST INCIDENCE (DAYS) |   619          610          576          ---       |   367          675          603          702       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.400      P=0.645      P=0.231      P=0.723N   |  P=0.568N     P=0.513N     P=0.297N     P=0.633N   |
|INCIDENTAL TUMOR       |  P=0.013N*    P=0.521N     P=0.592N     P=0.040N*  |  P=0.537      P=0.549N     P=0.415N     P=0.637    |
|LOGISTIC REGRESSION    |  P=0.079N     P=0.661      P=0.356      P=0.163N   |  P=0.560      P=0.432N     P=0.339N     P=0.661N   |
|COCHRAN-ARMITAGE       |  P=0.143N                                          |  P=0.573                                           |
|FISHER EXACT           |               P=0.661N     P=0.357      P=0.121N   |               P=0.500N     P=0.309N     P=0.661N   |
|=================================================================================================================================|
|                                                                                                                                 |
|Skin                                                                                                                             |
|     Fibrosarcoma                                                                                                                |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |    #            #            #            #        |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  0/50 (0%)    0/50 (0%)    2/50 (4%)    0/50 (0%)  |  1/50 (2%)    1/50 (2%)    1/50 (2%)    2/50 (4%)  |
|ADJUSTED (b)           |   0.0%         0.0%         5.9%         0.0%      |   2.8%         3.0%         2.2%         6.5%      |
|TERMINAL (d)           |  0/13 (0%)    0/7 (0%)     0/4 (0%)     0/0        |  0/24 (0%)    0/27 (0%)    0/31 (0%)    1/28 (4%)  |
|FIRST INCIDENCE (DAYS) |   ---          ---          576          ---       |   660          675          603          702       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.345        (e)        P=0.226        (e)      |  P=0.376      P=0.754      P=0.746N     P=0.536    |
|INCIDENTAL TUMOR       |  P=0.550N       (e)        P=0.445        (e)      |  P=0.305      P=0.620      P=0.672      P=0.432    |
|LOGISTIC REGRESSION    |  P=0.590        (e)        P=0.236        (e)      |  P=0.350      P=0.760      P=0.750      P=0.501    |
|COCHRAN-ARMITAGE       |  P=0.561                                           |  P=0.348                                           |
|FISHER EXACT           |                 (e)        P=0.247        (e)      |               P=0.753N     P=0.753N     P=0.500    |
|=================================================================================================================================|
         DATE: 12/27/96                     EXPERIMENT: 88035 TEST: 05                                                 PAGE  15
                              STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- 3-7PRIMACLONE

                                                 TERMINAL SACRIFICE AT 104 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   0 PPM        600 PPM      1300 PPM     2500 PPM  |   0 PPM        600 PPM      1300 PPM     2500 PPM  |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Skin                                                                                                                             |
|     Fibrosarcoma, Sarcoma, Myxosarcoma, or Fibrous Histiocytoma                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |    #            #            #            #        |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  0/50 (0%)    0/50 (0%)    2/50 (4%)    0/50 (0%)  |  2/50 (4%)    1/50 (2%)    1/50 (2%)    2/50 (4%)  |
|ADJUSTED (b)           |   0.0%         0.0%         5.9%         0.0%      |   4.7%         3.0%         2.2%         6.5%      |
|TERMINAL (d)           |  0/13 (0%)    0/7 (0%)     0/4 (0%)     0/0        |  0/24 (0%)    0/27 (0%)    0/31 (0%)    1/28 (4%)  |
|FIRST INCIDENCE (DAYS) |   ---          ---          576          ---       |   367          675          603          702       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.345        (e)        P=0.226        (e)      |  P=0.579      P=0.506N     P=0.485N     P=0.664N   |
|INCIDENTAL TUMOR       |  P=0.550N       (e)        P=0.445        (e)      |  P=0.501      P=0.566N     P=0.588N     P=0.663    |
|LOGISTIC REGRESSION    |  P=0.590        (e)        P=0.236        (e)      |  P=0.530      P=0.395N     P=0.552N     P=0.696N   |
|COCHRAN-ARMITAGE       |  P=0.561                                           |  P=0.553                                           |
|FISHER EXACT           |                 (e)        P=0.247        (e)      |               P=0.500N     P=0.500N     P=0.691N   |
|=================================================================================================================================|
|                                                                                                                                 |
|Skin                                                                                                                             |
|     Squamous Cell Papilloma, Papilloma, Squamous Cell Carcinoma or Keratoacanthoma                                              |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |    #            #            #            #        |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  1/50 (2%)    2/50 (4%)    1/50 (2%)    1/50 (2%)  |  0/50 (0%)    0/50 (0%)    1/50 (2%)    0/50 (0%)  |
|ADJUSTED (b)           |   7.7%         6.1%        14.3%         3.4%      |   0.0%         0.0%         3.2%         0.0%      |
|TERMINAL (d)           |  1/13 (8%)    0/7 (0%)     0/4 (0%)     0/0        |  0/24 (0%)    0/27 (0%)    1/31 (3%)    0/28 (0%)  |
|FIRST INCIDENCE (DAYS) |   723 (T)      562          697          562       |   ---          ---          722 (T)      ---       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.241      P=0.433      P=0.496      P=0.426    |  P=0.689        (e)        P=0.551        (e)      |
|INCIDENTAL TUMOR       |  P=0.583      P=0.480      P=0.633      P=0.742    |  P=0.689        (e)        P=0.551        (e)      |
|LOGISTIC REGRESSION    |  P=0.619      P=0.501      P=0.578      P=0.666    |  P=0.689        (e)        P=0.551        (e)      |
|COCHRAN-ARMITAGE       |  P=0.519N                                          |  P=0.667                                           |
|FISHER EXACT           |               P=0.500      P=0.753N     P=0.753N   |                 (e)        P=0.500        (e)      |
|=================================================================================================================================|
         DATE: 12/27/96                     EXPERIMENT: 88035 TEST: 05                                                 PAGE  16
                              STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- 3-7PRIMACLONE

                                                 TERMINAL SACRIFICE AT 104 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   0 PPM        600 PPM      1300 PPM     2500 PPM  |   0 PPM        600 PPM      1300 PPM     2500 PPM  |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Skin                                                                                                                             |
|     Squamous Cell Papilloma, Papilloma, or Keratoacanthoma                                                                      |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |    #            #            #            #        |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  1/50 (2%)    2/50 (4%)    1/50 (2%)    1/50 (2%)  |  0/50 (0%)    0/50 (0%)    1/50 (2%)    0/50 (0%)  |
|ADJUSTED (b)           |   7.7%         6.1%        14.3%         3.4%      |   0.0%         0.0%         3.2%         0.0%      |
|TERMINAL (d)           |  1/13 (8%)    0/7 (0%)     0/4 (0%)     0/0        |  0/24 (0%)    0/27 (0%)    1/31 (3%)    0/28 (0%)  |
|FIRST INCIDENCE (DAYS) |   723 (T)      562          697          562       |   ---          ---          722 (T)      ---       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.241      P=0.433      P=0.496      P=0.426    |  P=0.689        (e)        P=0.551        (e)      |
|INCIDENTAL TUMOR       |  P=0.583      P=0.480      P=0.633      P=0.742    |  P=0.689        (e)        P=0.551        (e)      |
|LOGISTIC REGRESSION    |  P=0.619      P=0.501      P=0.578      P=0.666    |  P=0.689        (e)        P=0.551        (e)      |
|COCHRAN-ARMITAGE       |  P=0.519N                                          |  P=0.667                                           |
|FISHER EXACT           |               P=0.500      P=0.753N     P=0.753N   |                 (e)        P=0.500        (e)      |
|=================================================================================================================================|
|                                                                                                                                 |
|Spleen                                                                                                                           |
|     Fibrosarcoma                                                                                                                |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  3/50 (6%)    1/50 (2%)    0/50 (0%)    0/49 (0%)  |  0/49 (0%)    0/50 (0%)    0/50 (0%)    1/50 (2%)  |
|ADJUSTED (b)           |  12.9%         3.7%         0.0%         0.0%      |   0.0%         0.0%         0.0%         2.3%      |
|TERMINAL (d)           |  1/13 (8%)    0/7 (0%)     0/4 (0%)     0/0        |  0/24 (0%)    0/27 (0%)    0/31 (0%)    0/28 (0%)  |
|FIRST INCIDENCE (DAYS) |   575          661          ---          ---       |   ---          ---          ---          550       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.147N     P=0.367N     P=0.210N     P=0.565N   |  P=0.194        (e)          (e)        P=0.491    |
|INCIDENTAL TUMOR       |  P=0.062N     P=0.312N     P=0.122N     P=0.253N   |  P=0.189        (e)          (e)        P=0.477    |
|LOGISTIC REGRESSION    |  P=0.045N*    P=0.304N     P=0.124N     P=0.210N   |  P=0.161        (e)          (e)        P=0.494    |
|COCHRAN-ARMITAGE       |  P=0.042N*                                         |  P=0.196                                           |
|FISHER EXACT           |               P=0.309N     P=0.121N     P=0.125N   |                 (e)          (e)        P=0.505    |
|=================================================================================================================================|
         DATE: 12/27/96                     EXPERIMENT: 88035 TEST: 05                                                 PAGE  17
                              STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- 3-7PRIMACLONE

                                                 TERMINAL SACRIFICE AT 104 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   0 PPM        600 PPM      1300 PPM     2500 PPM  |   0 PPM        600 PPM      1300 PPM     2500 PPM  |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Testes                                                                                                                           |
|     Adenoma                                                                                                                     |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            | 41/50 (82%)  44/50 (88%)  42/50 (84%)  43/48 (90%) |                                                    |
|ADJUSTED (b)           | 100.0%       100.0%       100.0%       100.0%      |                                                    |
|TERMINAL (d)           | 13/13 (100%)  7/7 (100%)   4/4 (100%)   0/0        |                                                    |
|FIRST INCIDENCE (DAYS) |   463          502          551          437       |                                                    |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P<0.001 **   P=0.070      P=0.003 **   P<0.001 ** |                                                    |
|INCIDENTAL TUMOR       |  P=0.042 *    P=0.235      P=0.545      P=0.032 *  |                                                    |
|LOGISTIC REGRESSION    |  P=0.009 **   P=0.387      P=0.559      P=0.009 ** |                                                    |
|COCHRAN-ARMITAGE       |  P=0.233                                           |                                                    |
|FISHER EXACT           |               P=0.288      P=0.500      P=0.217    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Thyroid Gland: C-Cell                                                                                                            |
|     Adenoma                                                                                                                     |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  7/50 (14%)   3/50 (6%)    7/49 (14%)   1/49 (2%)  |  5/49 (10%)   2/50 (4%)    7/50 (14%)   4/50 (8%)  |
|ADJUSTED (b)           |  43.3%        30.3%        46.7%        16.7%      |  19.4%         5.1%        22.6%        12.6%      |
|TERMINAL (d)           |  5/13 (38%)   2/7 (29%)    0/4 (0%)     0/0        |  4/24 (17%)   0/27 (0%)    7/31 (23%)   3/28 (11%) |
|FIRST INCIDENCE (DAYS) |   505          583          529          619       |   682          578          722 (T)      491       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.171      P=0.396N     P=0.114      P=0.589    |  P=0.541N     P=0.210N     P=0.565      P=0.420N   |
|INCIDENTAL TUMOR       |  P=0.351N     P=0.328N     P=0.281      P=0.468N   |  P=0.560N     P=0.238N     P=0.528      P=0.415N   |
|LOGISTIC REGRESSION    |  P=0.365N     P=0.173N     P=0.510      P=0.546N   |  P=0.535      P=0.227N     P=0.536      P=0.493N   |
|COCHRAN-ARMITAGE       |  P=0.066N                                          |  P=0.521                                           |
|FISHER EXACT           |               P=0.159N     P=0.597      P=0.032N*  |               P=0.210N     P=0.394      P=0.487N   |
|=================================================================================================================================|
         DATE: 12/27/96                     EXPERIMENT: 88035 TEST: 05                                                 PAGE  18
                              STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- 3-7PRIMACLONE

                                                 TERMINAL SACRIFICE AT 104 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   0 PPM        600 PPM      1300 PPM     2500 PPM  |   0 PPM        600 PPM      1300 PPM     2500 PPM  |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Thyroid Gland: C-Cell                                                                                                            |
|     Carcinoma or Adenoma                                                                                                        |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  8/50 (16%)   3/50 (6%)    8/49 (16%)   1/49 (2%)  |  5/49 (10%)   2/50 (4%)    7/50 (14%)   4/50 (8%)  |
|ADJUSTED (b)           |  45.4%        30.3%        48.5%        16.7%      |  19.4%         5.1%        22.6%        12.6%      |
|TERMINAL (d)           |  5/13 (38%)   2/7 (29%)    0/4 (0%)     0/0        |  4/24 (17%)   0/27 (0%)    7/31 (23%)   3/28 (11%) |
|FIRST INCIDENCE (DAYS) |   505          583          529          619       |   682          578          722 (T)      491       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.177      P=0.279N     P=0.118      P=0.607    |  P=0.541N     P=0.210N     P=0.565      P=0.420N   |
|INCIDENTAL TUMOR       |  P=0.259N     P=0.217N     P=0.333      P=0.442N   |  P=0.560N     P=0.238N     P=0.528      P=0.415N   |
|LOGISTIC REGRESSION    |  P=0.298N     P=0.108N     P=0.509      P=0.415N   |  P=0.535      P=0.227N     P=0.536      P=0.493N   |
|COCHRAN-ARMITAGE       |  P=0.049N*                                         |  P=0.521                                           |
|FISHER EXACT           |               P=0.100N     P=0.590      P=0.017N*  |               P=0.210N     P=0.394      P=0.487N   |
|=================================================================================================================================|
|                                                                                                                                 |
|Thyroid Gland: Follicular Cell                                                                                                   |
|     Adenoma                                                                                                                     |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  1/50 (2%)    1/50 (2%)    6/49 (12%)   3/49 (6%)  |  0/49 (0%)    0/50 (0%)    0/50 (0%)    0/50 (0%)  |
|ADJUSTED (b)           |   5.0%         4.5%        21.7%        10.7%      |   0.0%         0.0%         0.0%         0.0%      |
|TERMINAL (d)           |  0/13 (0%)    0/7 (0%)     0/4 (0%)     0/0        |  0/24 (0%)    0/27 (0%)    0/31 (0%)    0/28 (0%)  |
|FIRST INCIDENCE (DAYS) |   697          673          354          529       |   ---          ---          ---          ---       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.003 **   P=0.726      P=0.026 *    P=0.069    |    (e)          (e)          (e)          (e)      |
|INCIDENTAL TUMOR       |  P=0.160      P=0.742N     P=0.052      P=0.407    |    (e)          (e)          (e)          (e)      |
|LOGISTIC REGRESSION    |  P=0.227      P=0.754      P=0.047 *    P=0.280    |    (e)          (e)          (e)          (e)      |
|COCHRAN-ARMITAGE       |  P=0.136                                           |    (e)                                             |
|FISHER EXACT           |               P=0.753N     P=0.053      P=0.301    |                 (e)          (e)          (e)      |
|=================================================================================================================================|
         DATE: 12/27/96                     EXPERIMENT: 88035 TEST: 05                                                 PAGE  19
                              STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- 3-7PRIMACLONE

                                                 TERMINAL SACRIFICE AT 104 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   0 PPM        600 PPM      1300 PPM     2500 PPM  |   0 PPM        600 PPM      1300 PPM     2500 PPM  |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Thyroid Gland: Follicular Cell                                                                                                   |
|     Carcinoma                                                                                                                   |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  1/50 (2%)    3/50 (6%)    1/49 (2%)    1/49 (2%)  |  1/49 (2%)    0/50 (0%)    0/50 (0%)    0/50 (0%)  |
|ADJUSTED (b)           |   7.7%        20.6%         5.6%         5.6%      |   4.2%         0.0%         0.0%         0.0%      |
|TERMINAL (d)           |  1/13 (8%)    1/7 (14%)    0/4 (0%)     0/0        |  1/24 (4%)    0/27 (0%)    0/31 (0%)    0/28 (0%)  |
|FIRST INCIDENCE (DAYS) |   723 (T)      641          667          589       |   722 (T)      ---          ---          ---       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.135      P=0.196      P=0.583      P=0.356    |  P=0.273N     P=0.477N     P=0.449N     P=0.469N   |
|INCIDENTAL TUMOR       |  P=0.526      P=0.235      P=0.633      P=0.737    |  P=0.273N     P=0.477N     P=0.449N     P=0.469N   |
|LOGISTIC REGRESSION    |  P=0.461      P=0.281      P=0.662      P=0.583    |  P=0.273N     P=0.477N     P=0.449N     P=0.469N   |
|COCHRAN-ARMITAGE       |  P=0.438N                                          |  P=0.293N                                          |
|FISHER EXACT           |               P=0.309      P=0.747      P=0.747    |               P=0.495N     P=0.495N     P=0.495N   |
|=================================================================================================================================|
|                                                                                                                                 |
|Thyroid Gland: Follicular Cell                                                                                                   |
|     Carcinoma or Adenoma                                                                                                        |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  2/50 (4%)    4/50 (8%)    7/49 (14%)   4/49 (8%)  |  1/49 (2%)    0/50 (0%)    0/50 (0%)    0/50 (0%)  |
|ADJUSTED (b)           |  12.3%        24.2%        26.1%        15.7%      |   4.2%         0.0%         0.0%         0.0%      |
|TERMINAL (d)           |  1/13 (8%)    1/7 (14%)    0/4 (0%)     0/0        |  1/24 (4%)    0/27 (0%)    0/31 (0%)    0/28 (0%)  |
|FIRST INCIDENCE (DAYS) |   697          641          354          529       |   722 (T)      ---          ---          ---       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P<0.001 **   P=0.225      P=0.024 *    P=0.023 *  |  P=0.273N     P=0.477N     P=0.449N     P=0.469N   |
|INCIDENTAL TUMOR       |  P=0.155      P=0.292      P=0.049 *    P=0.317    |  P=0.273N     P=0.477N     P=0.449N     P=0.469N   |
|LOGISTIC REGRESSION    |  P=0.266      P=0.309      P=0.076      P=0.207    |  P=0.273N     P=0.477N     P=0.449N     P=0.469N   |
|COCHRAN-ARMITAGE       |  P=0.262                                           |  P=0.293N                                          |
|FISHER EXACT           |               P=0.339      P=0.075      P=0.329    |               P=0.495N     P=0.495N     P=0.495N   |
|=================================================================================================================================|
         DATE: 12/27/96                     EXPERIMENT: 88035 TEST: 05                                                 PAGE  20
                              STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- 3-7PRIMACLONE

                                                 TERMINAL SACRIFICE AT 104 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   0 PPM        600 PPM      1300 PPM     2500 PPM  |   0 PPM        600 PPM      1300 PPM     2500 PPM  |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Uterus                                                                                                                           |
|     Polyp Stromal                                                                                                               |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |                                                    |  8/50 (16%)   7/50 (14%)   6/50 (12%)   7/50 (14%) |
|ADJUSTED (b)           |                                                    |  24.9%        21.1%        19.4%        19.9%      |
|TERMINAL (d)           |                                                    |  4/24 (17%)   3/27 (11%)   6/31 (19%)   3/28 (11%) |
|FIRST INCIDENCE (DAYS) |                                                    |   415          612          722 (T)      489       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |                                                    |  P=0.356N     P=0.488N     P=0.245N     P=0.433N   |
|INCIDENTAL TUMOR       |                                                    |  P=0.438N     P=0.570N     P=0.312N     P=0.496N   |
|LOGISTIC REGRESSION    |                                                    |  P=0.429N     P=0.517N     P=0.375N     P=0.498N   |
|COCHRAN-ARMITAGE       |                                                    |  P=0.439N                                          |
|FISHER EXACT           |                                                    |               P=0.500N     P=0.387N     P=0.500N   |
|=================================================================================================================================|
|                                                                                                                                 |
|Uterus                                                                                                                           |
|     Sarcoma Stromal                                                                                                             |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |                                                    |  0/50 (0%)    3/50 (6%)    0/50 (0%)    3/50 (6%)  |
|ADJUSTED (b)           |                                                    |   0.0%         7.9%         0.0%         9.3%      |
|TERMINAL (d)           |                                                    |  0/24 (0%)    1/27 (4%)    0/31 (0%)    2/28 (7%)  |
|FIRST INCIDENCE (DAYS) |                                                    |   ---          415          ---          561       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |                                                    |  P=0.192      P=0.123        (e)        P=0.137    |
|INCIDENTAL TUMOR       |                                                    |  P=0.177      P=0.215        (e)        P=0.134    |
|LOGISTIC REGRESSION    |                                                    |  P=0.149      P=0.178        (e)        P=0.121    |
|COCHRAN-ARMITAGE       |                                                    |  P=0.175                                           |
|FISHER EXACT           |                                                    |               P=0.121        (e)        P=0.121    |
|=================================================================================================================================|
         DATE: 12/27/96                     EXPERIMENT: 88035 TEST: 05                                                 PAGE  21
                              STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- 3-7PRIMACLONE

                                                 TERMINAL SACRIFICE AT 104 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   0 PPM        600 PPM      1300 PPM     2500 PPM  |   0 PPM        600 PPM      1300 PPM     2500 PPM  |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Uterus                                                                                                                           |
|     Sarcoma Stromal or Polyp Stromal                                                                                            |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |                                                    |  8/50 (16%)  10/50 (20%)   6/50 (12%)  10/50 (20%) |
|ADJUSTED (b)           |                                                    |  24.9%        27.7%        19.4%        28.1%      |
|TERMINAL (d)           |                                                    |  4/24 (17%)   4/27 (15%)   6/31 (19%)   5/28 (18%) |
|FIRST INCIDENCE (DAYS) |                                                    |   415          415          722 (T)      489       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |                                                    |  P=0.529      P=0.414      P=0.245N     P=0.476    |
|INCIDENTAL TUMOR       |                                                    |  P=0.441      P=0.407      P=0.312N     P=0.412    |
|LOGISTIC REGRESSION    |                                                    |  P=0.433      P=0.427      P=0.375N     P=0.399    |
|COCHRAN-ARMITAGE       |                                                    |  P=0.436                                           |
|FISHER EXACT           |                                                    |               P=0.398      P=0.387N     P=0.398    |
|=================================================================================================================================|
|                                                                                                                                 |
|Vagina                                                                                                                           |
|     Polyp                                                                                                                       |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |                                                    |  1/50 (2%)    0/50 (0%)    0/50 (0%)    2/50 (4%)  |
|ADJUSTED (b)           |                                                    |   2.7%         0.0%         0.0%         5.9%      |
|TERMINAL (d)           |                                                    |  0/24 (0%)    0/27 (0%)    0/31 (0%)    1/28 (4%)  |
|FIRST INCIDENCE (DAYS) |                                                    |   646          ---          ---          596       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |                                                    |  P=0.258      P=0.523N     P=0.484N     P=0.510    |
|INCIDENTAL TUMOR       |                                                    |  P=0.234      P=0.623N     P=0.573N     P=0.462    |
|LOGISTIC REGRESSION    |                                                    |  P=0.242      P=0.492N     P=0.509N     P=0.501    |
|COCHRAN-ARMITAGE       |                                                    |  P=0.246                                           |
|FISHER EXACT           |                                                    |               P=0.500N     P=0.500N     P=0.500    |
|=================================================================================================================================|
         DATE: 12/27/96                     EXPERIMENT: 88035 TEST: 05                                                 PAGE  22
                              STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- 3-7PRIMACLONE

                                                 TERMINAL SACRIFICE AT 104 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   0 PPM        600 PPM      1300 PPM     2500 PPM  |   0 PPM        600 PPM      1300 PPM     2500 PPM  |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|All Organs                                                                                                                       |
|     Leukemia: Lymphocytic, Monocytic, Mononuclear, or Undifferentiated                                                          |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |    #            #            #            #        |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            | 35/50 (70%)  30/50 (60%)  24/50 (48%)  12/50 (24%) | 13/50 (26%)  13/50 (26%)  13/50 (26%)  22/50 (44%) |
|ADJUSTED (b)           |  84.4%        79.3%       100.0%       100.0%      |  38.3%        31.7%        31.3%        53.0%      |
|TERMINAL (d)           |  7/13 (54%)   2/7 (29%)    4/4 (100%)   0/0        |  6/24 (25%)   4/27 (15%)   5/31 (16%)  10/28 (36%) |
|FIRST INCIDENCE (DAYS) |   505          502          354          380       |   561          367          501          477       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.043 *    P=0.529      P=0.414      P=0.039 *  |  P=0.068      P=0.574      P=0.415N     P=0.114    |
|INCIDENTAL TUMOR       |  P<0.001N**   P=0.068N     P=0.003N**   P<0.001N** |  P=0.016 *    P=0.555N     P=0.475      P=0.041 *  |
|LOGISTIC REGRESSION    |  P<0.001N**   P=0.059N     P=0.023N*    P<0.001N** |  P=0.018 *    P=0.483N     P=0.582      P=0.047 *  |
|COCHRAN-ARMITAGE       |  P<0.001N**                                        |  P=0.024 *                                         |
|FISHER EXACT           |               P=0.201N     P=0.021N*    P<0.001N** |               P=0.590N     P=0.590N     P=0.046 *  |
|=================================================================================================================================|
|                                                                                                                                 |
|All Organs                                                                                                                       |
|     Mesothelioma: Benign, Malignant, NOS                                                                                        |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |    #            #            #            #        |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  2/50 (4%)    3/50 (6%)    2/50 (4%)    1/50 (2%)  |  0/50 (0%)    0/50 (0%)    0/50 (0%)    0/50 (0%)  |
|ADJUSTED (b)           |  15.4%        18.4%        13.9%         2.5%      |   0.0%         0.0%         0.0%         0.0%      |
|TERMINAL (d)           |  2/13 (15%)   1/7 (14%)    0/4 (0%)     0/0        |  0/24 (0%)    0/27 (0%)    0/31 (0%)    0/28 (0%)  |
|FIRST INCIDENCE (DAYS) |   723 (T)      544          627          533       |   ---          ---          ---          ---       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.261      P=0.341      P=0.389      P=0.486    |    (e)          (e)          (e)          (e)      |
|INCIDENTAL TUMOR       |  P=0.424N     P=0.380      P=0.573      P=0.705    |    (e)          (e)          (e)          (e)      |
|LOGISTIC REGRESSION    |  P=0.472N     P=0.499      P=0.555      P=0.739    |    (e)          (e)          (e)          (e)      |
|COCHRAN-ARMITAGE       |  P=0.307N                                          |    (e)                                             |
|FISHER EXACT           |               P=0.500      P=0.691N     P=0.500N   |                 (e)          (e)          (e)      |
|=================================================================================================================================|
         DATE: 12/27/96                     EXPERIMENT: 88035 TEST: 05                                                 PAGE  23
                              STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- 3-7PRIMACLONE

                                                 TERMINAL SACRIFICE AT 104 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   0 PPM        600 PPM      1300 PPM     2500 PPM  |   0 PPM        600 PPM      1300 PPM     2500 PPM  |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|All Organs                                                                                                                       |
|     Benign Tumors                                                                                                               |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |    #            #            #            #        |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            | 49/50 (98%)  49/50 (98%)  49/50 (98%)  44/50 (88%) | 39/50 (78%)  35/50 (70%)  35/50 (70%)  33/50 (66%) |
|ADJUSTED (b)           | 100.0%       100.0%       100.0%       100.0%      |  90.5%        87.2%        77.5%        79.8%      |
|TERMINAL (d)           | 13/13 (100%)  7/7 (100%)   4/4 (100%)   0/0        | 20/24 (83%)  22/27 (81%)  21/31 (68%)  20/28 (71%) |
|FIRST INCIDENCE (DAYS) |   281          502          354          436       |   415          410          389          489       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P<0.001 **   P=0.158      P=0.008 **   P<0.001 ** |  P=0.069N     P=0.240N     P=0.060N     P=0.083N   |
|INCIDENTAL TUMOR       |  P=0.080N     P=0.729N     P=0.555      P=0.283N   |  P=0.121N     P=0.410N     P=0.248N     P=0.138N   |
|LOGISTIC REGRESSION    |  P=0.043N*    P=0.666N     P=0.761N     P=0.127N   |  P=0.102N     P=0.439N     P=0.216N     P=0.134N   |
|COCHRAN-ARMITAGE       |  P=0.009N**                                        |  P=0.134N                                          |
|FISHER EXACT           |               P=0.753N     P=0.753N     P=0.056N   |               P=0.247N     P=0.247N     P=0.133N   |
|=================================================================================================================================|
|                                                                                                                                 |
|All Organs                                                                                                                       |
|     Malignant Tumors                                                                                                            |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |    #            #            #            #        |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            | 41/50 (82%)  35/50 (70%)  29/50 (58%)  15/50 (30%) | 21/50 (42%)  20/50 (40%)  17/50 (34%)  28/50 (56%) |
|ADJUSTED (b)           |  90.6%        88.8%       100.0%       100.0%      |  52.1%        46.7%        39.1%        63.6%      |
|TERMINAL (d)           |  9/13 (69%)   4/7 (57%)    4/4 (100%)   0/0        |  7/24 (29%)   7/27 (26%)   7/31 (23%)  13/28 (46%) |
|FIRST INCIDENCE (DAYS) |   305          502          354          380       |   367          367          389          433       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.026 *    P=0.518      P=0.392      P=0.032 *  |  P=0.213      P=0.508N     P=0.165N     P=0.258    |
|INCIDENTAL TUMOR       |  P<0.001N**   P=0.062N     P=0.004N**   P<0.001N** |  P=0.052      P=0.490N     P=0.401N     P=0.086    |
|LOGISTIC REGRESSION    |  P<0.001N**   P=0.061N     P=0.008N**   P<0.001N** |  P=0.059      P=0.351N     P=0.327N     P=0.114    |
|COCHRAN-ARMITAGE       |  P<0.001N**                                        |  P=0.086                                           |
|FISHER EXACT           |               P=0.121N     P=0.008N**   P<0.001N** |               P=0.500N     P=0.268N     P=0.115    |
|=================================================================================================================================|
         DATE: 12/27/96                     EXPERIMENT: 88035 TEST: 05                                                 PAGE  24
                              STATISTICAL ANALYSIS OF PRIMARY TUMORS IN RATS(FISCHER344) -- 3-7PRIMACLONE

                                                 TERMINAL SACRIFICE AT 104 WEEKS

|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   0 PPM        600 PPM      1300 PPM     2500 PPM  |   0 PPM        600 PPM      1300 PPM     2500 PPM  |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|All Organs                                                                                                                       |
|     Malignant and Benign Tumors                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |    #            #            #            #        |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            | 50/50 (100%) 49/50 (98%)  50/50 (100%) 47/50 (94%) | 47/50 (94%)  44/50 (88%)  41/50 (82%)  46/50 (92%) |
|ADJUSTED (b)           | 100.0%       100.0%       100.0%       100.0%      |  94.0%        89.7%        82.0%        92.0%      |
|TERMINAL (d)           | 13/13 (100%)  7/7 (100%)   4/4 (100%)   0/0        | 21/24 (88%)  22/27 (81%)  22/31 (71%)  24/28 (86%) |
|FIRST INCIDENCE (DAYS) |   281          502          354          380       |   367          367          389          433       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P<0.001 **   P=0.189      P=0.008 **   P<0.001 ** |  P=0.243N     P=0.352N     P=0.042N*    P=0.288N   |
|INCIDENTAL TUMOR       |  P=0.069N     P=0.362N       (e)        P=0.196N   |  P=0.547N     P=0.256N     P=0.129N     P=0.586N   |
|LOGISTIC REGRESSION    |  P=0.091N     P=0.248N       (e)        P=0.172N   |  P=0.551      P=0.237N     P=0.129N     P=0.586N   |
|COCHRAN-ARMITAGE       |  P=0.046N*                                         |  P=0.452N                                          |
|FISHER EXACT           |               P=0.500N     P=1.000N     P=0.121N   |               P=0.243N     P=0.061N     P=0.500N   |
|=================================================================================================================================|

 (a)  Number of tumor-bearing animals / number of animals examined at site.
 (b)  Kaplan-Meier estimated lifetime tumor incidence after adjustment for 
      intercurrent mortality.
 (d)  Observed incidence at terminal kill.
 (f)  Beneath the control incidence are the P-values associated with the trend 
      test.  Beneath the dosed group incidence are the P-values corresponding to 
      pairwise comparisons between the controls and that dosed group.  The life
      table analysis regards tumors in animals dying  prior to terminal kill as
      being (directly or indirectly) the cause of death.  The incidental tumor 
      test regards these lesions as non-fatal.  Logistic regression is an alternative
      method for analyzing the incidence of non-fatal tumors.  The Cochran-Armitage
      and Fisher's exact tests compare directly the overall incidence rates.  
      For all tests, a negative trend is indicated by "N".
 (e)  Value of Statistic cannot be computed. 
 (I)  Interim sacrifice
 (T)  Terminal sacrifice
  #   Tumor rates based on number of animals necropsied.

  *   To the right of any statistical result, indicates significance at (P<=0.05).
  **  To the right of any statistical result, indicates significance at (P<=0.01).