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TDMS Study 05185-04 Pathology Tables

NTP                                        STATISTICAL ANALYSIS OF PRIMARY TUMORS                              REPORT: PEIRPT08     
LAB: IITRI                                               ISOBUTYL NITRITE (IBN)                                DATE: 05/20/95       
EXPERIMENT: 05185 TEST: 04                                                                                     TIME: 11:45:29       
TEST TYPE:  CHRONIC                             CAGES FROM 0000 TO LAST CAGE                                   PAGE:       1        
CONT: N01 ES 65143                              ROUTE: RESPIRATORY EXPOSURE WHOLE BODY                         NTP C#: 61052B       
PATHOLOGIST: RICHARD LONG                                                                                      CAS: 542-56-3        
------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
               REASONS FOR REMOVAL:    ALL                                                                                          
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
                                                                                                                                    
               REMOVAL DATE RANGE:     ALL                                                                                          
                                                                                                                                    
               TREATMENT GROUPS:       INCLUDE ALL                                                                                  
NTP                                        STATISTICAL ANALYSIS OF PRIMARY TUMORS                              REPORT: PEIRPT08     
LAB: IITRI                                               ISOBUTYL NITRITE (IBN)                                DATE: 05/20/95       
EXPERIMENT: 05185 TEST: 04                                                                                     TIME: 11:45:29       
TEST TYPE:  CHRONIC                             CAGES FROM 0000 TO LAST CAGE                                                        
CONT: N01 ES 65143                              ROUTE: RESPIRATORY EXPOSURE WHOLE BODY                         NTP C#: 61052B       
PATHOLOGIST: RICHARD LONG                                                                                      CAS: 542-56-3        


                                                    MICE(B6C3F1)
                                              ----------------------------
             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
                                                    Epididymis
                                                    Gallbladder
                                                    Heart
                                                    Islets, Pancreatic
                                                    Kidney
                                                    Larynx
                                                    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: IITRI                                               ISOBUTYL NITRITE (IBN)                                DATE: 05/20/95       
EXPERIMENT: 05185 TEST: 04                                                                                     TIME: 11:45:29       
TEST TYPE:  CHRONIC                             CAGES FROM 0000 TO LAST CAGE                                                        
CONT: N01 ES 65143                              ROUTE: RESPIRATORY EXPOSURE WHOLE BODY                         NTP C#: 61052B       
PATHOLOGIST: RICHARD LONG                                                                                      CAS: 542-56-3        


                                     SUMMARY OF STATISTICALLY SIGNIFICANT (P<=.05) RESULTS
                                     IN THE ANALYSIS OF THE STUDY OF ISOBUTYL NITRITE (IBN)
              ====================================================================================================
                                                           MALE MICE
                                                          -------------
                  ORGAN                               MORPHOLOGY
                 -------                             ------------
              Lung                          Alveolar/Bronchiolar Adenoma
                                            Alveolar/Bronchiolar Carcinoma or Alveolar/Bronchiolar Adenoma
              Thyroid Gland: Follicular Cell
                                            Adenoma
                                            Carcinoma or Adenoma
              All Organs                    Benign Tumors
                                            Malignant and Benign Tumors
              ====================================================================================================
                                                           FEMALE MICE
                                                          -------------
                  ORGAN                               MORPHOLOGY
                 -------                             ------------
              Lung                          Alveolar/Bronchiolar Adenoma
                                            Alveolar/Bronchiolar Carcinoma or Alveolar/Bronchiolar Adenoma
              Uterus                        Sarcoma Stromal or Polyp Stromal
              All Organs                    Benign Tumors
                                            Malignant and Benign Tumors
              ====================================================================================================
         DATE: 05/20/95                     EXPERIMENT: 05185 TEST: 04                                                 PAGE   1
                           STATISTICAL ANALYSIS OF PRIMARY TUMORS IN MICE(B6C3F1) -- ISOBUTYL NITRITE (IBN)
                                                 MALE TERMINAL SACRIFICE AT 104 WEEKS
                                                 FEMALE TERMINAL SACRIFICE AT 105 WEEKS
|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   CONTROL      37.5 PPM     75 PPM       150 PPM   |   CONTROL      37.5 PPM     75 PPM       150 PPM   |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Adrenal Medulla                                                                                                                  |
|     Pheochromocytoma Benign                                                                                                     |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  0/59 (0%)    2/59 (3%)    0/58 (0%)    1/58 (2%)  |  0/55 (0%)    0/58 (0%)    2/54 (4%)    2/57 (4%)  |
|ADJUSTED (b)           |   0.0%         5.9%         0.0%         2.4%      |   0.0%         0.0%         6.1%         5.7%      |
|INTERIM SACRIFICE 1 (c)|  0/10 (0%)    0/10 (0%)    0/10 (0%)    0/7 (0%)   |  0/8 (0%)     0/9 (0%)     0/9 (0%)     0/10 (0%)  |
|TERMINAL (d)           |  0/37 (0%)    2/34 (6%)    0/35 (0%)    0/29 (0%)  |  0/29 (0%)    0/40 (0%)    2/33 (6%)    2/35 (6%)  |
|FIRST INCIDENCE (DAYS) |   ---          725 (T)      ---          556       |   ---          ---          729 (T)      729 (T)   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.500      P=0.220        (e)        P=0.495    |  P=0.092        (e)        P=0.267      P=0.280    |
|INCIDENTAL TUMOR       |  P=0.575      P=0.220        (e)        P=0.617    |  P=0.092        (e)        P=0.267      P=0.280    |
|LOGISTIC REGRESSION    |  P=0.525      P=0.220        (e)        P=0.508    |  P=0.092        (e)        P=0.267      P=0.280    |
|COCHRAN-ARMITAGE       |  P=0.537                                           |  P=0.088                                           |
|FISHER EXACT           |               P=0.248        (e)        P=0.496    |                 (e)        P=0.243      P=0.257    |
|=================================================================================================================================|
|                                                                                                                                 |
|Adrenal Medulla                                                                                                                  |
|     Pheochromocytoma: Benign, Complex, Malignant, NOS                                                                           |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  0/59 (0%)    2/59 (3%)    0/58 (0%)    1/58 (2%)  |  0/55 (0%)    1/58 (2%)    2/54 (4%)    2/57 (4%)  |
|ADJUSTED (b)           |   0.0%         5.9%         0.0%         2.4%      |   0.0%         2.0%         6.1%         5.7%      |
|INTERIM SACRIFICE 1 (c)|  0/10 (0%)    0/10 (0%)    0/10 (0%)    0/7 (0%)   |  0/8 (0%)     0/9 (0%)     0/9 (0%)     0/10 (0%)  |
|TERMINAL (d)           |  0/37 (0%)    2/34 (6%)    0/35 (0%)    0/29 (0%)  |  0/29 (0%)    0/40 (0%)    2/33 (6%)    2/35 (6%)  |
|FIRST INCIDENCE (DAYS) |   ---          725 (T)      ---          556       |   ---          512          729 (T)      729 (T)   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.500      P=0.220        (e)        P=0.495    |  P=0.167      P=0.504      P=0.267      P=0.280    |
|INCIDENTAL TUMOR       |  P=0.575      P=0.220        (e)        P=0.617    |  P=0.207        (e)        P=0.267      P=0.280    |
|LOGISTIC REGRESSION    |  P=0.525      P=0.220        (e)        P=0.508    |  P=0.158      P=0.467      P=0.267      P=0.280    |
|COCHRAN-ARMITAGE       |  P=0.537                                           |  P=0.164                                           |
|FISHER EXACT           |               P=0.248        (e)        P=0.496    |               P=0.513      P=0.243      P=0.257    |
|=================================================================================================================================|
         DATE: 05/20/95                     EXPERIMENT: 05185 TEST: 04                                                 PAGE   2
                           STATISTICAL ANALYSIS OF PRIMARY TUMORS IN MICE(B6C3F1) -- ISOBUTYL NITRITE (IBN)
                                                 MALE TERMINAL SACRIFICE AT 104 WEEKS
                                                 FEMALE TERMINAL SACRIFICE AT 105 WEEKS
|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   CONTROL      37.5 PPM     75 PPM       150 PPM   |   CONTROL      37.5 PPM     75 PPM       150 PPM   |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Harderian Gland                                                                                                                  |
|     Adenoma                                                                                                                     |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |    #            #            #            #        |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  4/60 (7%)    1/60 (2%)    3/60 (5%)    5/60 (8%)  |  0/60 (0%)    1/60 (2%)    1/59 (2%)    2/60 (3%)  |
|ADJUSTED (b)           |  10.5%         2.9%         8.6%        16.7%      |   0.0%         2.2%         2.8%         5.4%      |
|INTERIM SACRIFICE 1 (c)|  0/10 (0%)    0/10 (0%)    0/10 (0%)    0/7 (0%)   |  0/9 (0%)     0/9 (0%)     0/9 (0%)     0/10 (0%)  |
|TERMINAL (d)           |  3/37 (8%)    1/35 (3%)    3/35 (9%)    5/30 (17%) |  0/32 (0%)    0/42 (0%)    1/36 (3%)    2/37 (5%)  |
|FIRST INCIDENCE (DAYS) |   711          725 (T)      725 (T)      725 (T)   |   ---          697          729 (T)      729 (T)   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.176      P=0.198N     P=0.532N     P=0.373    |  P=0.162      P=0.556      P=0.523      P=0.271    |
|INCIDENTAL TUMOR       |  P=0.187      P=0.092N     P=0.431N     P=0.476    |  P=0.145      P=0.362      P=0.523      P=0.271    |
|LOGISTIC REGRESSION    |  P=0.189      P=0.162N     P=0.520N     P=0.416    |  P=0.152      P=0.513      P=0.523      P=0.271    |
|COCHRAN-ARMITAGE       |  P=0.264                                           |  P=0.154                                           |
|FISHER EXACT           |               P=0.182N     P=0.500N     P=0.500    |               P=0.500      P=0.496      P=0.248    |
|=================================================================================================================================|
|                                                                                                                                 |
|Harderian Gland                                                                                                                  |
|     Carcinoma or Adenoma                                                                                                        |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |    #            #            #            #        |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  4/60 (7%)    1/60 (2%)    3/60 (5%)    6/60 (10%) |  0/60 (0%)    1/60 (2%)    1/59 (2%)    2/60 (3%)  |
|ADJUSTED (b)           |  10.5%         2.9%         8.6%        20.0%      |   0.0%         2.2%         2.8%         5.4%      |
|INTERIM SACRIFICE 1 (c)|  0/10 (0%)    0/10 (0%)    0/10 (0%)    0/7 (0%)   |  0/9 (0%)     0/9 (0%)     0/9 (0%)     0/10 (0%)  |
|TERMINAL (d)           |  3/37 (8%)    1/35 (3%)    3/35 (9%)    6/30 (20%) |  0/32 (0%)    0/42 (0%)    1/36 (3%)    2/37 (5%)  |
|FIRST INCIDENCE (DAYS) |   711          725 (T)      725 (T)      725 (T)   |   ---          697          729 (T)      729 (T)   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.088      P=0.198N     P=0.532N     P=0.247    |  P=0.162      P=0.556      P=0.523      P=0.271    |
|INCIDENTAL TUMOR       |  P=0.093      P=0.092N     P=0.431N     P=0.330    |  P=0.145      P=0.362      P=0.523      P=0.271    |
|LOGISTIC REGRESSION    |  P=0.095      P=0.162N     P=0.520N     P=0.284    |  P=0.152      P=0.513      P=0.523      P=0.271    |
|COCHRAN-ARMITAGE       |  P=0.152                                           |  P=0.154                                           |
|FISHER EXACT           |               P=0.182N     P=0.500N     P=0.372    |               P=0.500      P=0.496      P=0.248    |
|=================================================================================================================================|
         DATE: 05/20/95                     EXPERIMENT: 05185 TEST: 04                                                 PAGE   3
                           STATISTICAL ANALYSIS OF PRIMARY TUMORS IN MICE(B6C3F1) -- ISOBUTYL NITRITE (IBN)
                                                 MALE TERMINAL SACRIFICE AT 104 WEEKS
                                                 FEMALE TERMINAL SACRIFICE AT 105 WEEKS
|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   CONTROL      37.5 PPM     75 PPM       150 PPM   |   CONTROL      37.5 PPM     75 PPM       150 PPM   |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Islets, Pancreatic                                                                                                               |
|     Adenoma                                                                                                                     |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  2/5 (40%)    1/3 (33%)    2/9 (22%)    0/1 (0%)   |  0/2 (0%)     1/2 (50%)    0/3 (0%)     0/3 (0%)   |
|ADJUSTED (b)           |  40.0%        50.0%        16.6%         0.0%      |   0.0%        50.0%         0.0%         0.0%      |
|INTERIM SACRIFICE 1 (c)|  0/0          0/1 (0%)     0/0          0/0        |  0/0          0/0          0/0          0/0        |
|TERMINAL (d)           |  2/5 (40%)    1/2 (50%)    1/7 (14%)    0/1 (0%)   |  0/2 (0%)     1/2 (50%)    0/1 (0%)     0/2 (0%)   |
|FIRST INCIDENCE (DAYS) |   725 (T)      725 (T)      681          ---       |   ---          729 (T)      ---          ---       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.343N     P=0.712      P=0.610N     P=0.638N   |  P=0.569N     P=0.500        (e)          (e)      |
|INCIDENTAL TUMOR       |  P=0.253N     P=0.712      P=0.373N     P=0.638N   |  P=0.569N     P=0.500        (e)          (e)      |
|LOGISTIC REGRESSION    |  P=0.333N     P=0.712      P=0.488N     P=0.638N   |  P=0.569N     P=0.500        (e)          (e)      |
|COCHRAN-ARMITAGE       |  P=0.320N                                          |  P=0.497N                                          |
|FISHER EXACT           |               P=0.714N     P=0.455N     P=0.667N   |               P=0.500        (e)          (e)      |
|=================================================================================================================================|
|                                                                                                                                 |
|Liver                                                                                                                            |
|     Hemangiosarcoma                                                                                                             |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  2/60 (3%)    2/60 (3%)    1/60 (2%)    3/60 (5%)  |  0/60 (0%)    0/60 (0%)    0/59 (0%)    0/60 (0%)  |
|ADJUSTED (b)           |   5.1%         5.6%         2.9%         7.6%      |   0.0%         0.0%         0.0%         0.0%      |
|INTERIM SACRIFICE 1 (c)|  0/10 (0%)    0/10 (0%)    0/10 (0%)    0/7 (0%)   |  0/9 (0%)     0/9 (0%)     0/9 (0%)     0/10 (0%)  |
|TERMINAL (d)           |  1/37 (3%)    1/35 (3%)    1/35 (3%)    0/30 (0%)  |  0/32 (0%)    0/42 (0%)    0/36 (0%)    0/37 (0%)  |
|FIRST INCIDENCE (DAYS) |   604          724          725 (T)      553       |   ---          ---          ---          ---       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.345      P=0.692N     P=0.510N     P=0.460    |    (e)          (e)          (e)          (e)      |
|INCIDENTAL TUMOR       |  P=0.533      P=0.607N     P=0.459N     P=0.616N   |    (e)          (e)          (e)          (e)      |
|LOGISTIC REGRESSION    |  P=0.384      P=0.672N     P=0.496N     P=0.655    |    (e)          (e)          (e)          (e)      |
|COCHRAN-ARMITAGE       |  P=0.404                                           |    (e)                                             |
|FISHER EXACT           |               P=0.691N     P=0.500N     P=0.500    |                 (e)          (e)          (e)      |
|=================================================================================================================================|
         DATE: 05/20/95                     EXPERIMENT: 05185 TEST: 04                                                 PAGE   4
                           STATISTICAL ANALYSIS OF PRIMARY TUMORS IN MICE(B6C3F1) -- ISOBUTYL NITRITE (IBN)
                                                 MALE TERMINAL SACRIFICE AT 104 WEEKS
                                                 FEMALE TERMINAL SACRIFICE AT 105 WEEKS
|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   CONTROL      37.5 PPM     75 PPM       150 PPM   |   CONTROL      37.5 PPM     75 PPM       150 PPM   |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Liver                                                                                                                            |
|     Hepatocellular Adenoma                                                                                                      |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            | 16/60 (27%)  16/60 (27%)  18/60 (30%)  16/60 (27%) |  7/60 (12%)  10/60 (17%)   7/59 (12%)   6/60 (10%) |
|ADJUSTED (b)           |  36.7%        38.8%        38.7%        40.0%      |  19.3%        23.8%        19.4%        15.8%      |
|INTERIM SACRIFICE 1 (c)|  2/10 (20%)   1/10 (10%)   4/10 (40%)   2/7 (29%)  |  1/9 (11%)    0/9 (0%)     0/9 (0%)     0/10 (0%)  |
|TERMINAL (d)           | 11/37 (30%)  11/35 (31%)   9/35 (26%)   8/30 (27%) |  5/32 (16%)  10/42 (24%)   7/36 (19%)   5/37 (14%) |
|FIRST INCIDENCE (DAYS) |   455          457 (I)      457 (I)      457 (I)   |   458 (I)      729 (T)      729 (T)      724       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.268      P=0.550      P=0.387      P=0.345    |  P=0.269N     P=0.512      P=0.534N     P=0.396N   |
|INCIDENTAL TUMOR       |  P=0.449      P=0.365N     P=0.560      P=0.580    |  P=0.293N     P=0.467      P=0.572N     P=0.463N   |
|LOGISTIC REGRESSION    |  P=0.465      P=0.519N     P=0.429      P=0.540    |  P=0.317N     P=0.376      P=0.612      P=0.490N   |
|COCHRAN-ARMITAGE       |  P=0.519                                           |  P=0.322N                                          |
|FISHER EXACT           |               P=0.582N     P=0.420      P=0.582N   |               P=0.301      P=0.598      P=0.500N   |
|=================================================================================================================================|
|                                                                                                                                 |
|Liver                                                                                                                            |
|     Hepatocellular Carcinoma                                                                                                    |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            | 13/60 (22%)   7/60 (12%)  11/60 (18%)   9/60 (15%) |  4/60 (7%)    5/60 (8%)    2/59 (3%)    5/60 (8%)  |
|ADJUSTED (b)           |  27.2%        15.8%        24.7%        23.6%      |   9.8%        10.8%         5.6%        13.0%      |
|INTERIM SACRIFICE 1 (c)|  1/10 (10%)   1/10 (10%)   0/10 (0%)    0/7 (0%)   |  0/9 (0%)     1/9 (11%)    0/9 (0%)     0/10 (0%)  |
|TERMINAL (d)           |  5/37 (14%)   2/35 (6%)    3/35 (9%)    3/30 (10%) |  1/32 (3%)    3/42 (7%)    2/36 (6%)    4/37 (11%) |
|FIRST INCIDENCE (DAYS) |   455          457 (I)      484          552       |   572          458 (I)      729 (T)      716       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.460N     P=0.116N     P=0.418N     P=0.358N   |  P=0.531      P=0.606      P=0.321N     P=0.564    |
|INCIDENTAL TUMOR       |  P=0.190N     P=0.104N     P=0.351N     P=0.159N   |  P=0.418      P=0.304      P=0.426N     P=0.347    |
|LOGISTIC REGRESSION    |  P=0.165N     P=0.136N     P=0.265N     P=0.157N   |  P=0.487      P=0.505      P=0.343N     P=0.500    |
|COCHRAN-ARMITAGE       |  P=0.322N                                          |  P=0.500                                           |
|FISHER EXACT           |               P=0.110N     P=0.410N     P=0.240N   |               P=0.500      P=0.348N     P=0.500    |
|=================================================================================================================================|
         DATE: 05/20/95                     EXPERIMENT: 05185 TEST: 04                                                 PAGE   5
                           STATISTICAL ANALYSIS OF PRIMARY TUMORS IN MICE(B6C3F1) -- ISOBUTYL NITRITE (IBN)
                                                 MALE TERMINAL SACRIFICE AT 104 WEEKS
                                                 FEMALE TERMINAL SACRIFICE AT 105 WEEKS
|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   CONTROL      37.5 PPM     75 PPM       150 PPM   |   CONTROL      37.5 PPM     75 PPM       150 PPM   |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Liver                                                                                                                            |
|     Hepatocellular Carcinoma or Hepatocellular Adenoma                                                                          |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            | 27/60 (45%)  21/60 (35%)  24/60 (40%)  18/60 (30%) | 11/60 (18%)  14/60 (23%)   7/59 (12%)  10/60 (17%) |
|ADJUSTED (b)           |  54.1%        47.5%        48.6%        43.3%      |  27.6%        31.4%        19.4%        25.6%      |
|INTERIM SACRIFICE 1 (c)|  3/10 (30%)   2/10 (20%)   4/10 (40%)   2/7 (29%)  |  1/9 (11%)    1/9 (11%)    0/9 (0%)     0/10 (0%)  |
|TERMINAL (d)           | 15/37 (41%)  13/35 (37%)  11/35 (31%)   8/30 (27%) |  6/32 (19%)  12/42 (29%)   7/36 (19%)   8/37 (22%) |
|FIRST INCIDENCE (DAYS) |   455          457 (I)      457 (I)      457 (I)   |   458 (I)      458 (I)      729 (T)      716       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.292N     P=0.215N     P=0.406N     P=0.241N   |  P=0.249N     P=0.568      P=0.173N     P=0.380N   |
|INCIDENTAL TUMOR       |  P=0.087N     P=0.119N     P=0.282N     P=0.057N   |  P=0.332N     P=0.335      P=0.243N     P=0.584N   |
|LOGISTIC REGRESSION    |  P=0.074N     P=0.150N     P=0.266N     P=0.066N   |  P=0.314N     P=0.379      P=0.226N     P=0.497N   |
|COCHRAN-ARMITAGE       |  P=0.082N                                          |  P=0.303N                                          |
|FISHER EXACT           |               P=0.176N     P=0.356N     P=0.066N   |               P=0.327      P=0.234N     P=0.500N   |
|=================================================================================================================================|
|                                                                                                                                 |
|Liver                                                                                                                            |
|     Hepatocellular Carcinoma, Hepatocellular Adenoma, or Hepatoblastoma                                                         |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            | 27/60 (45%)  21/60 (35%)  24/60 (40%)  18/60 (30%) | 11/60 (18%)  14/60 (23%)   7/59 (12%)  10/60 (17%) |
|ADJUSTED (b)           |  54.1%        47.5%        48.6%        43.3%      |  27.6%        31.4%        19.4%        25.6%      |
|INTERIM SACRIFICE 1 (c)|  3/10 (30%)   2/10 (20%)   4/10 (40%)   2/7 (29%)  |  1/9 (11%)    1/9 (11%)    0/9 (0%)     0/10 (0%)  |
|TERMINAL (d)           | 15/37 (41%)  13/35 (37%)  11/35 (31%)   8/30 (27%) |  6/32 (19%)  12/42 (29%)   7/36 (19%)   8/37 (22%) |
|FIRST INCIDENCE (DAYS) |   455          457 (I)      457 (I)      457 (I)   |   458 (I)      458 (I)      729 (T)      716       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.292N     P=0.215N     P=0.406N     P=0.241N   |  P=0.249N     P=0.568      P=0.173N     P=0.380N   |
|INCIDENTAL TUMOR       |  P=0.087N     P=0.119N     P=0.282N     P=0.057N   |  P=0.332N     P=0.335      P=0.243N     P=0.584N   |
|LOGISTIC REGRESSION    |  P=0.074N     P=0.150N     P=0.266N     P=0.066N   |  P=0.314N     P=0.379      P=0.226N     P=0.497N   |
|COCHRAN-ARMITAGE       |  P=0.082N                                          |  P=0.303N                                          |
|FISHER EXACT           |               P=0.176N     P=0.356N     P=0.066N   |               P=0.327      P=0.234N     P=0.500N   |
|=================================================================================================================================|
         DATE: 05/20/95                     EXPERIMENT: 05185 TEST: 04                                                 PAGE   6
                           STATISTICAL ANALYSIS OF PRIMARY TUMORS IN MICE(B6C3F1) -- ISOBUTYL NITRITE (IBN)
                                                 MALE TERMINAL SACRIFICE AT 104 WEEKS
                                                 FEMALE TERMINAL SACRIFICE AT 105 WEEKS
|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   CONTROL      37.5 PPM     75 PPM       150 PPM   |   CONTROL      37.5 PPM     75 PPM       150 PPM   |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Lung                                                                                                                             |
|     Alveolar/Bronchiolar Adenoma                                                                                                |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  8/60 (13%)  14/60 (23%)  13/59 (22%)  17/60 (28%) |  4/60 (7%)   16/60 (27%)   9/59 (15%)  19/60 (32%) |
|ADJUSTED (b)           |  19.7%        36.6%        37.1%        49.2%      |  11.7%        35.6%        21.4%        45.3%      |
|INTERIM SACRIFICE 1 (c)|  1/10 (10%)   2/10 (20%)   0/10 (0%)    0/7 (0%)   |  0/9 (0%)     2/9 (22%)    2/9 (22%)    2/10 (20%) |
|TERMINAL (d)           |  6/37 (16%)  12/35 (34%)  13/35 (37%)  13/30 (43%) |  3/32 (9%)   14/42 (33%)   6/36 (17%)  15/37 (41%) |
|FIRST INCIDENCE (DAYS) |   457 (I)      457 (I)      725 (T)      558       |   689          458 (I)      458 (I)      458 (I)   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.007 **   P=0.096      P=0.131      P=0.010 ** |  P=0.005 **   P=0.015 *    P=0.153      P=0.002 ** |
|INCIDENTAL TUMOR       |  P=0.014 *    P=0.083      P=0.142      P=0.025 *  |  P=0.003 **   P=0.012 *    P=0.120      P<0.001 ** |
|LOGISTIC REGRESSION    |  P=0.019 *    P=0.144      P=0.159      P=0.021 *  |  P=0.002 **   P=0.005 **   P=0.115      P<0.001 ** |
|COCHRAN-ARMITAGE       |  P=0.045 *                                         |  P=0.003 **                                        |
|FISHER EXACT           |               P=0.119      P=0.158      P=0.035 *  |               P=0.003 **   P=0.113      P<0.001 ** |
|=================================================================================================================================|
|                                                                                                                                 |
|Lung                                                                                                                             |
|     Alveolar/Bronchiolar Carcinoma                                                                                              |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  1/60 (2%)    6/60 (10%)   5/59 (8%)    4/60 (7%)  |  2/60 (3%)    2/60 (3%)    2/59 (3%)    2/60 (3%)  |
|ADJUSTED (b)           |   2.7%        15.6%        14.3%        11.2%      |   5.7%         4.8%         5.6%         5.4%      |
|INTERIM SACRIFICE 1 (c)|  0/10 (0%)    0/10 (0%)    0/10 (0%)    0/7 (0%)   |  0/9 (0%)     0/9 (0%)     0/9 (0%)     0/10 (0%)  |
|TERMINAL (d)           |  1/37 (3%)    4/35 (11%)   5/35 (14%)   2/30 (7%)  |  1/32 (3%)    2/42 (5%)    2/36 (6%)    2/37 (5%)  |
|FIRST INCIDENCE (DAYS) |   725 (T)      667          725 (T)      558       |   690          729 (T)      729 (T)      729 (T)   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.210      P=0.059      P=0.090      P=0.142    |  P=0.575N     P=0.602N     P=0.662N     P=0.647N   |
|INCIDENTAL TUMOR       |  P=0.290      P=0.139      P=0.090      P=0.208    |  P=0.596      P=0.684N     P=0.668      P=0.693    |
|LOGISTIC REGRESSION    |  P=0.249      P=0.071      P=0.090      P=0.170    |  P=0.588N     P=0.646N     P=0.688N     P=0.676N   |
|COCHRAN-ARMITAGE       |  P=0.301                                           |  P=0.595                                           |
|FISHER EXACT           |               P=0.057      P=0.100      P=0.182    |               P=0.691N     P=0.684      P=0.691N   |
|=================================================================================================================================|
         DATE: 05/20/95                     EXPERIMENT: 05185 TEST: 04                                                 PAGE   7
                           STATISTICAL ANALYSIS OF PRIMARY TUMORS IN MICE(B6C3F1) -- ISOBUTYL NITRITE (IBN)
                                                 MALE TERMINAL SACRIFICE AT 104 WEEKS
                                                 FEMALE TERMINAL SACRIFICE AT 105 WEEKS
|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   CONTROL      37.5 PPM     75 PPM       150 PPM   |   CONTROL      37.5 PPM     75 PPM       150 PPM   |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Lung                                                                                                                             |
|     Alveolar/Bronchiolar Carcinoma or Alveolar/Bronchiolar Adenoma                                                              |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  9/60 (15%)  18/60 (30%)  16/59 (27%)  19/60 (32%) |  6/60 (10%)  17/60 (28%)  11/59 (19%)  21/60 (35%) |
|ADJUSTED (b)           |  22.3%        44.8%        45.7%        53.4%      |  17.0%        37.9%        26.6%        50.3%      |
|INTERIM SACRIFICE 1 (c)|  1/10 (10%)   2/10 (20%)   0/10 (0%)    0/7 (0%)   |  0/9 (0%)     2/9 (22%)    2/9 (22%)    2/10 (20%) |
|TERMINAL (d)           |  7/37 (19%)  14/35 (40%)  16/35 (46%)  14/30 (47%) |  4/32 (13%)  15/42 (36%)   8/36 (22%)  17/37 (46%) |
|FIRST INCIDENCE (DAYS) |   457 (I)      457 (I)      725 (T)      558       |   689          458 (I)      458 (I)      458 (I)   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.007 **   P=0.032 *    P=0.058      P=0.006 ** |  P=0.005 **   P=0.043 *    P=0.193      P=0.003 ** |
|INCIDENTAL TUMOR       |  P=0.017 *    P=0.051      P=0.064      P=0.017 *  |  P=0.003 **   P=0.027 *    P=0.137      P=0.001 ** |
|LOGISTIC REGRESSION    |  P=0.019 *    P=0.053      P=0.077      P=0.014 *  |  P=0.003 **   P=0.015 *    P=0.140      P<0.001 ** |
|COCHRAN-ARMITAGE       |  P=0.050                                           |  P=0.004 **                                        |
|FISHER EXACT           |               P=0.040 *    P=0.081      P=0.025 *  |               P=0.010 **   P=0.139      P<0.001 ** |
|=================================================================================================================================|
|                                                                                                                                 |
|Mammary Gland                                                                                                                    |
|     Carcinoma or Adenoma                                                                                                        |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |    #            #            #            #        |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  0/60 (0%)    0/60 (0%)    0/60 (0%)    0/60 (0%)  |  0/60 (0%)    0/60 (0%)    2/59 (3%)    0/60 (0%)  |
|ADJUSTED (b)           |   0.0%         0.0%         0.0%         0.0%      |   0.0%         0.0%         5.6%         0.0%      |
|INTERIM SACRIFICE 1 (c)|  0/10 (0%)    0/10 (0%)    0/10 (0%)    0/7 (0%)   |  0/9 (0%)     0/9 (0%)     0/9 (0%)     0/10 (0%)  |
|TERMINAL (d)           |  0/37 (0%)    0/35 (0%)    0/35 (0%)    0/30 (0%)  |  0/32 (0%)    0/42 (0%)    2/36 (6%)    0/37 (0%)  |
|FIRST INCIDENCE (DAYS) |   ---          ---          ---          ---       |   ---          ---          729 (T)      ---       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |    (e)          (e)          (e)          (e)      |  P=0.607        (e)        P=0.264        (e)      |
|INCIDENTAL TUMOR       |    (e)          (e)          (e)          (e)      |  P=0.607        (e)        P=0.264        (e)      |
|LOGISTIC REGRESSION    |    (e)          (e)          (e)          (e)      |  P=0.607        (e)        P=0.264        (e)      |
|COCHRAN-ARMITAGE       |    (e)                                             |  P=0.593                                           |
|FISHER EXACT           |                 (e)          (e)          (e)      |                 (e)        P=0.244        (e)      |
|=================================================================================================================================|
         DATE: 05/20/95                     EXPERIMENT: 05185 TEST: 04                                                 PAGE   8
                           STATISTICAL ANALYSIS OF PRIMARY TUMORS IN MICE(B6C3F1) -- ISOBUTYL NITRITE (IBN)
                                                 MALE TERMINAL SACRIFICE AT 104 WEEKS
                                                 FEMALE TERMINAL SACRIFICE AT 105 WEEKS
|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   CONTROL      37.5 PPM     75 PPM       150 PPM   |   CONTROL      37.5 PPM     75 PPM       150 PPM   |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Mammary Gland                                                                                                                    |
|     Fibroma, Fibroadenoma, Carcinoma, or Adenoma                                                                                |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |    #            #            #            #        |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  0/60 (0%)    0/60 (0%)    0/60 (0%)    0/60 (0%)  |  0/60 (0%)    0/60 (0%)    2/59 (3%)    0/60 (0%)  |
|ADJUSTED (b)           |   0.0%         0.0%         0.0%         0.0%      |   0.0%         0.0%         5.6%         0.0%      |
|INTERIM SACRIFICE 1 (c)|  0/10 (0%)    0/10 (0%)    0/10 (0%)    0/7 (0%)   |  0/9 (0%)     0/9 (0%)     0/9 (0%)     0/10 (0%)  |
|TERMINAL (d)           |  0/37 (0%)    0/35 (0%)    0/35 (0%)    0/30 (0%)  |  0/32 (0%)    0/42 (0%)    2/36 (6%)    0/37 (0%)  |
|FIRST INCIDENCE (DAYS) |   ---          ---          ---          ---       |   ---          ---          729 (T)      ---       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |    (e)          (e)          (e)          (e)      |  P=0.607        (e)        P=0.264        (e)      |
|INCIDENTAL TUMOR       |    (e)          (e)          (e)          (e)      |  P=0.607        (e)        P=0.264        (e)      |
|LOGISTIC REGRESSION    |    (e)          (e)          (e)          (e)      |  P=0.607        (e)        P=0.264        (e)      |
|COCHRAN-ARMITAGE       |    (e)                                             |  P=0.593                                           |
|FISHER EXACT           |                 (e)          (e)          (e)      |                 (e)        P=0.244        (e)      |
|=================================================================================================================================|
|                                                                                                                                 |
|Ovary                                                                                                                            |
|     Cystadenoma                                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |                                                    |  1/58 (2%)    0/59 (0%)    2/55 (4%)    1/59 (2%)  |
|ADJUSTED (b)           |                                                    |   3.3%         0.0%         5.6%         2.7%      |
|INTERIM SACRIFICE 1 (c)|                                                    |  0/9 (0%)     0/9 (0%)     0/9 (0%)     0/10 (0%)  |
|TERMINAL (d)           |                                                    |  1/30 (3%)    0/41 (0%)    1/32 (3%)    1/37 (3%)  |
|FIRST INCIDENCE (DAYS) |                                                    |   729 (T)      ---          663          729 (T)   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |                                                    |  P=0.521      P=0.438N     P=0.515      P=0.715N   |
|INCIDENTAL TUMOR       |                                                    |  P=0.491      P=0.438N     P=0.437      P=0.715N   |
|LOGISTIC REGRESSION    |                                                    |  P=0.505      P=0.438N     P=0.483      P=0.715N   |
|COCHRAN-ARMITAGE       |                                                    |  P=0.500                                           |
|FISHER EXACT           |                                                    |               P=0.496N     P=0.480      P=0.748N   |
|=================================================================================================================================|
         DATE: 05/20/95                     EXPERIMENT: 05185 TEST: 04                                                 PAGE   9
                           STATISTICAL ANALYSIS OF PRIMARY TUMORS IN MICE(B6C3F1) -- ISOBUTYL NITRITE (IBN)
                                                 MALE TERMINAL SACRIFICE AT 104 WEEKS
                                                 FEMALE TERMINAL SACRIFICE AT 105 WEEKS
|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   CONTROL      37.5 PPM     75 PPM       150 PPM   |   CONTROL      37.5 PPM     75 PPM       150 PPM   |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Pituitary Gland: Pars Distalis or Unspecified Site                                                                               |
|     Adenoma                                                                                                                     |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  0/56 (0%)    0/56 (0%)    1/54 (2%)    1/54 (2%)  | 12/56 (21%)  19/56 (34%)  18/59 (31%)  13/57 (23%) |
|ADJUSTED (b)           |   0.0%         0.0%         2.9%         3.8%      |  34.2%        47.5%        47.1%        34.6%      |
|INTERIM SACRIFICE 1 (c)|  0/9 (0%)     0/10 (0%)    0/8 (0%)     0/7 (0%)   |  0/8 (0%)     0/8 (0%)     0/9 (0%)     0/10 (0%)  |
|TERMINAL (d)           |  0/36 (0%)    0/32 (0%)    1/34 (3%)    1/26 (4%)  |  9/31 (29%)  19/40 (48%)  16/36 (44%)  11/35 (31%) |
|FIRST INCIDENCE (DAYS) |   ---          ---          725 (T)      725 (T)   |   635          729 (T)      585          583       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.182        (e)        P=0.489      P=0.435    |  P=0.420N     P=0.305      P=0.248      P=0.563N   |
|INCIDENTAL TUMOR       |  P=0.182        (e)        P=0.489      P=0.435    |  P=0.523N     P=0.178      P=0.183      P=0.413    |
|LOGISTIC REGRESSION    |  P=0.182        (e)        P=0.489      P=0.435    |  P=0.491N     P=0.169      P=0.163      P=0.509    |
|COCHRAN-ARMITAGE       |  P=0.228                                           |  P=0.445N                                          |
|FISHER EXACT           |                 (e)        P=0.491      P=0.491    |               P=0.102      P=0.185      P=0.520    |
|=================================================================================================================================|
|                                                                                                                                 |
|Pituitary Gland: Pars Intermedia                                                                                                 |
|     Adenoma                                                                                                                     |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  1/56 (2%)    1/56 (2%)    0/54 (0%)    0/54 (0%)  |  2/56 (4%)    2/56 (4%)    0/59 (0%)    0/57 (0%)  |
|ADJUSTED (b)           |   1.8%         3.1%         0.0%         0.0%      |   6.5%         4.8%         0.0%         0.0%      |
|INTERIM SACRIFICE 1 (c)|  1/9 (11%)    0/10 (0%)    0/8 (0%)     0/7 (0%)   |  0/8 (0%)     0/8 (0%)     0/9 (0%)     0/10 (0%)  |
|TERMINAL (d)           |  0/36 (0%)    1/32 (3%)    0/34 (0%)    0/26 (0%)  |  2/31 (6%)    1/40 (3%)    0/36 (0%)    0/35 (0%)  |
|FIRST INCIDENCE (DAYS) |   457 (I)      725 (T)      ---          ---       |   729 (T)      728          ---          ---       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.277N     P=0.759      P=0.523N     P=0.550N   |  P=0.077N     P=0.595N     P=0.206N     P=0.212N   |
|INCIDENTAL TUMOR       |  P=0.277N     P=0.759      P=0.523N     P=0.550N   |  P=0.094N     P=0.686      P=0.206N     P=0.212N   |
|LOGISTIC REGRESSION    |  P=0.229N     P=0.745      P=0.591N     P=0.472N   |  P=0.073N     P=0.598N     P=0.206N     P=0.212N   |
|COCHRAN-ARMITAGE       |  P=0.241N                                          |  P=0.082N                                          |
|FISHER EXACT           |               P=0.752N     P=0.509N     P=0.509N   |               P=0.691N     P=0.235N     P=0.243N   |
|=================================================================================================================================|
         DATE: 05/20/95                     EXPERIMENT: 05185 TEST: 04                                                 PAGE  10
                           STATISTICAL ANALYSIS OF PRIMARY TUMORS IN MICE(B6C3F1) -- ISOBUTYL NITRITE (IBN)
                                                 MALE TERMINAL SACRIFICE AT 104 WEEKS
                                                 FEMALE TERMINAL SACRIFICE AT 105 WEEKS
|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   CONTROL      37.5 PPM     75 PPM       150 PPM   |   CONTROL      37.5 PPM     75 PPM       150 PPM   |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Skin                                                                                                                             |
|     Fibroma, Fibrosarcoma, Sarcoma, Myxoma, Myxosarcoma, or Fibrous Histiocytoma                                                |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |    #            #            #            #        |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  0/60 (0%)    0/60 (0%)    0/60 (0%)    1/60 (2%)  |  1/60 (2%)    0/60 (0%)    2/59 (3%)    0/60 (0%)  |
|ADJUSTED (b)           |   0.0%         0.0%         0.0%         3.3%      |   3.1%         0.0%         4.5%         0.0%      |
|INTERIM SACRIFICE 1 (c)|  0/10 (0%)    0/10 (0%)    0/10 (0%)    0/7 (0%)   |  0/9 (0%)     0/9 (0%)     0/9 (0%)     0/10 (0%)  |
|TERMINAL (d)           |  0/37 (0%)    0/35 (0%)    0/35 (0%)    1/30 (3%)  |  1/32 (3%)    0/42 (0%)    1/36 (3%)    0/37 (0%)  |
|FIRST INCIDENCE (DAYS) |   ---          ---          ---          725 (T)   |   729 (T)      ---          434          ---       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.173        (e)          (e)        P=0.458    |  P=0.454N     P=0.446N     P=0.525      P=0.471N   |
|INCIDENTAL TUMOR       |  P=0.173        (e)          (e)        P=0.458    |  P=0.361N     P=0.446N     P=0.736N     P=0.471N   |
|LOGISTIC REGRESSION    |  P=0.173        (e)          (e)        P=0.458    |  P=0.459N     P=0.446N     P=0.492      P=0.471N   |
|COCHRAN-ARMITAGE       |  P=0.198                                           |  P=0.463N                                          |
|FISHER EXACT           |                 (e)          (e)        P=0.500    |               P=0.500N     P=0.494      P=0.500N   |
|=================================================================================================================================|
|                                                                                                                                 |
|Skin                                                                                                                             |
|     Fibrosarcoma, Sarcoma, Myxosarcoma, or Fibrous Histiocytoma                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |    #            #            #            #        |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  0/60 (0%)    0/60 (0%)    0/60 (0%)    1/60 (2%)  |  1/60 (2%)    0/60 (0%)    2/59 (3%)    0/60 (0%)  |
|ADJUSTED (b)           |   0.0%         0.0%         0.0%         3.3%      |   3.1%         0.0%         4.5%         0.0%      |
|INTERIM SACRIFICE 1 (c)|  0/10 (0%)    0/10 (0%)    0/10 (0%)    0/7 (0%)   |  0/9 (0%)     0/9 (0%)     0/9 (0%)     0/10 (0%)  |
|TERMINAL (d)           |  0/37 (0%)    0/35 (0%)    0/35 (0%)    1/30 (3%)  |  1/32 (3%)    0/42 (0%)    1/36 (3%)    0/37 (0%)  |
|FIRST INCIDENCE (DAYS) |   ---          ---          ---          725 (T)   |   729 (T)      ---          434          ---       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.173        (e)          (e)        P=0.458    |  P=0.454N     P=0.446N     P=0.525      P=0.471N   |
|INCIDENTAL TUMOR       |  P=0.173        (e)          (e)        P=0.458    |  P=0.361N     P=0.446N     P=0.736N     P=0.471N   |
|LOGISTIC REGRESSION    |  P=0.173        (e)          (e)        P=0.458    |  P=0.459N     P=0.446N     P=0.492      P=0.471N   |
|COCHRAN-ARMITAGE       |  P=0.198                                           |  P=0.463N                                          |
|FISHER EXACT           |                 (e)          (e)        P=0.500    |               P=0.500N     P=0.494      P=0.500N   |
|=================================================================================================================================|
         DATE: 05/20/95                     EXPERIMENT: 05185 TEST: 04                                                 PAGE  11
                           STATISTICAL ANALYSIS OF PRIMARY TUMORS IN MICE(B6C3F1) -- ISOBUTYL NITRITE (IBN)
                                                 MALE TERMINAL SACRIFICE AT 104 WEEKS
                                                 FEMALE TERMINAL SACRIFICE AT 105 WEEKS
|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   CONTROL      37.5 PPM     75 PPM       150 PPM   |   CONTROL      37.5 PPM     75 PPM       150 PPM   |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Thyroid Gland: Follicular Cell                                                                                                   |
|     Adenoma                                                                                                                     |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  1/60 (2%)    0/60 (0%)    0/60 (0%)    5/60 (8%)  |  4/60 (7%)    3/60 (5%)    2/59 (3%)    2/60 (3%)  |
|ADJUSTED (b)           |   2.7%         0.0%         0.0%        16.7%      |  11.6%         7.1%         5.6%         5.4%      |
|INTERIM SACRIFICE 1 (c)|  0/10 (0%)    0/10 (0%)    0/10 (0%)    0/7 (0%)   |  0/9 (0%)     0/9 (0%)     0/9 (0%)     0/10 (0%)  |
|TERMINAL (d)           |  1/37 (3%)    0/35 (0%)    0/35 (0%)    5/30 (17%) |  3/32 (9%)    3/42 (7%)    2/36 (6%)    2/37 (5%)  |
|FIRST INCIDENCE (DAYS) |   725 (T)      ---          ---          725 (T)   |   649          729 (T)      729 (T)      729 (T)   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.004 **   P=0.511N     P=0.511N     P=0.061    |  P=0.224N     P=0.366N     P=0.294N     P=0.282N   |
|INCIDENTAL TUMOR       |  P=0.004 **   P=0.511N     P=0.511N     P=0.061    |  P=0.240N     P=0.425N     P=0.342N     P=0.317N   |
|LOGISTIC REGRESSION    |  P=0.004 **   P=0.511N     P=0.511N     P=0.061    |  P=0.241N     P=0.430N     P=0.331N     P=0.317N   |
|COCHRAN-ARMITAGE       |  P=0.009 **                                        |  P=0.250N                                          |
|FISHER EXACT           |               P=0.500N     P=0.500N     P=0.103    |               P=0.500N     P=0.348N     P=0.340N   |
|=================================================================================================================================|
|                                                                                                                                 |
|Thyroid Gland: Follicular Cell                                                                                                   |
|     Carcinoma or Adenoma                                                                                                        |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |                                                    |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  1/60 (2%)    1/60 (2%)    0/60 (0%)    5/60 (8%)  |  4/60 (7%)    3/60 (5%)    2/59 (3%)    2/60 (3%)  |
|ADJUSTED (b)           |   2.7%         2.9%         0.0%        16.7%      |  11.6%         7.1%         5.6%         5.4%      |
|INTERIM SACRIFICE 1 (c)|  0/10 (0%)    0/10 (0%)    0/10 (0%)    0/7 (0%)   |  0/9 (0%)     0/9 (0%)     0/9 (0%)     0/10 (0%)  |
|TERMINAL (d)           |  1/37 (3%)    1/35 (3%)    0/35 (0%)    5/30 (17%) |  3/32 (9%)    3/42 (7%)    2/36 (6%)    2/37 (5%)  |
|FIRST INCIDENCE (DAYS) |   725 (T)      725 (T)      ---          725 (T)   |   649          729 (T)      729 (T)      729 (T)   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.011 *    P=0.749      P=0.511N     P=0.061    |  P=0.224N     P=0.366N     P=0.294N     P=0.282N   |
|INCIDENTAL TUMOR       |  P=0.011 *    P=0.749      P=0.511N     P=0.061    |  P=0.240N     P=0.425N     P=0.342N     P=0.317N   |
|LOGISTIC REGRESSION    |  P=0.011 *    P=0.749      P=0.511N     P=0.061    |  P=0.241N     P=0.430N     P=0.331N     P=0.317N   |
|COCHRAN-ARMITAGE       |  P=0.022 *                                         |  P=0.250N                                          |
|FISHER EXACT           |               P=0.752N     P=0.500N     P=0.103    |               P=0.500N     P=0.348N     P=0.340N   |
|=================================================================================================================================|
         DATE: 05/20/95                     EXPERIMENT: 05185 TEST: 04                                                 PAGE  12
                           STATISTICAL ANALYSIS OF PRIMARY TUMORS IN MICE(B6C3F1) -- ISOBUTYL NITRITE (IBN)
                                                 MALE TERMINAL SACRIFICE AT 104 WEEKS
                                                 FEMALE TERMINAL SACRIFICE AT 105 WEEKS
|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   CONTROL      37.5 PPM     75 PPM       150 PPM   |   CONTROL      37.5 PPM     75 PPM       150 PPM   |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|Uterus                                                                                                                           |
|     Polyp Stromal                                                                                                               |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |                                                    |  3/60 (5%)    2/60 (3%)    0/59 (0%)    1/60 (2%)  |
|ADJUSTED (b)           |                                                    |   9.4%         4.8%         0.0%         2.7%      |
|INTERIM SACRIFICE 1 (c)|                                                    |  0/9 (0%)     0/9 (0%)     0/9 (0%)     0/10 (0%)  |
|TERMINAL (d)           |                                                    |  3/32 (9%)    2/42 (5%)    0/36 (0%)    1/37 (3%)  |
|FIRST INCIDENCE (DAYS) |                                                    |   729 (T)      729 (T)      ---          729 (T)   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |                                                    |  P=0.146N     P=0.377N     P=0.101N     P=0.254N   |
|INCIDENTAL TUMOR       |                                                    |  P=0.146N     P=0.377N     P=0.101N     P=0.254N   |
|LOGISTIC REGRESSION    |                                                    |  P=0.146N     P=0.377N     P=0.101N     P=0.254N   |
|COCHRAN-ARMITAGE       |                                                    |  P=0.165N                                          |
|FISHER EXACT           |                                                    |               P=0.500N     P=0.125N     P=0.309N   |
|=================================================================================================================================|
|                                                                                                                                 |
|Uterus                                                                                                                           |
|     Sarcoma Stromal or Polyp Stromal                                                                                            |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |                                                    |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |                                                    |  4/60 (7%)    2/60 (3%)    0/59 (0%)    1/60 (2%)  |
|ADJUSTED (b)           |                                                    |  12.5%         4.8%         0.0%         2.7%      |
|INTERIM SACRIFICE 1 (c)|                                                    |  0/9 (0%)     0/9 (0%)     0/9 (0%)     0/10 (0%)  |
|TERMINAL (d)           |                                                    |  4/32 (13%)   2/42 (5%)    0/36 (0%)    1/37 (3%)  |
|FIRST INCIDENCE (DAYS) |                                                    |   729 (T)      729 (T)      ---          729 (T)   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |                                                    |  P=0.073N     P=0.220N     P=0.049N*    P=0.137N   |
|INCIDENTAL TUMOR       |                                                    |  P=0.073N     P=0.220N     P=0.049N*    P=0.137N   |
|LOGISTIC REGRESSION    |                                                    |  P=0.073N     P=0.220N     P=0.047N*    P=0.137N   |
|COCHRAN-ARMITAGE       |                                                    |  P=0.087N                                          |
|FISHER EXACT           |                                                    |               P=0.340N     P=0.061N     P=0.182N   |
|=================================================================================================================================|
         DATE: 05/20/95                     EXPERIMENT: 05185 TEST: 04                                                 PAGE  13
                           STATISTICAL ANALYSIS OF PRIMARY TUMORS IN MICE(B6C3F1) -- ISOBUTYL NITRITE (IBN)
                                                 MALE TERMINAL SACRIFICE AT 104 WEEKS
                                                 FEMALE TERMINAL SACRIFICE AT 105 WEEKS
|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   CONTROL      37.5 PPM     75 PPM       150 PPM   |   CONTROL      37.5 PPM     75 PPM       150 PPM   |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|All Organs                                                                                                                       |
|     Hemangioma                                                                                                                  |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |    #            #            #            #        |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  1/60 (2%)    0/60 (0%)    0/60 (0%)    0/60 (0%)  |  2/60 (3%)    1/60 (2%)    0/59 (0%)    1/60 (2%)  |
|ADJUSTED (b)           |   2.7%         0.0%         0.0%         0.0%      |   6.0%         2.4%         0.0%         2.5%      |
|INTERIM SACRIFICE 1 (c)|  0/10 (0%)    0/10 (0%)    0/10 (0%)    0/7 (0%)   |  0/9 (0%)     0/9 (0%)     0/9 (0%)     0/10 (0%)  |
|TERMINAL (d)           |  1/37 (3%)    0/35 (0%)    0/35 (0%)    0/30 (0%)  |  1/32 (3%)    1/42 (2%)    0/36 (0%)    0/37 (0%)  |
|FIRST INCIDENCE (DAYS) |   725 (T)      ---          ---          ---       |   709          729 (T)      ---          716       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.329N     P=0.511N     P=0.511N     P=0.542N   |  P=0.343N     P=0.410N     P=0.218N     P=0.439N   |
|INCIDENTAL TUMOR       |  P=0.329N     P=0.511N     P=0.511N     P=0.542N   |  P=0.418N     P=0.515N     P=0.299N     P=0.593N   |
|LOGISTIC REGRESSION    |  P=0.329N     P=0.511N     P=0.511N     P=0.542N   |  P=0.363N     P=0.443N     P=0.232N     P=0.482N   |
|COCHRAN-ARMITAGE       |  P=0.307N                                          |  P=0.368N                                          |
|FISHER EXACT           |               P=0.500N     P=0.500N     P=0.500N   |               P=0.500N     P=0.252N     P=0.500N   |
|=================================================================================================================================|
|                                                                                                                                 |
|All Organs                                                                                                                       |
|     Hemangiosarcoma                                                                                                             |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |    #            #            #            #        |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  2/60 (3%)    3/60 (5%)    2/60 (3%)    3/60 (5%)  |  1/60 (2%)    3/60 (5%)    0/59 (0%)    0/60 (0%)  |
|ADJUSTED (b)           |   5.1%         8.3%         5.7%         7.6%      |   2.6%         7.1%         0.0%         0.0%      |
|INTERIM SACRIFICE 1 (c)|  0/10 (0%)    0/10 (0%)    0/10 (0%)    0/7 (0%)   |  0/9 (0%)     0/9 (0%)     0/9 (0%)     0/10 (0%)  |
|TERMINAL (d)           |  1/37 (3%)    2/35 (6%)    2/35 (6%)    0/30 (0%)  |  0/32 (0%)    3/42 (7%)    0/36 (0%)    0/37 (0%)  |
|FIRST INCIDENCE (DAYS) |   604          724          725 (T)      553       |   690          729 (T)      ---          ---       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.384      P=0.495      P=0.681      P=0.460    |  P=0.141N     P=0.398      P=0.500N     P=0.485N   |
|INCIDENTAL TUMOR       |  P=0.555      P=0.594      P=0.668N     P=0.616N   |  P=0.163N     P=0.316      P=0.638N     P=0.594N   |
|LOGISTIC REGRESSION    |  P=0.427      P=0.532      P=0.692N     P=0.655    |  P=0.148N     P=0.354      P=0.502N     P=0.500N   |
|COCHRAN-ARMITAGE       |  P=0.457                                           |  P=0.152N                                          |
|FISHER EXACT           |               P=0.500      P=0.691N     P=0.500    |               P=0.309      P=0.504N     P=0.500N   |
|=================================================================================================================================|
         DATE: 05/20/95                     EXPERIMENT: 05185 TEST: 04                                                 PAGE  14
                           STATISTICAL ANALYSIS OF PRIMARY TUMORS IN MICE(B6C3F1) -- ISOBUTYL NITRITE (IBN)
                                                 MALE TERMINAL SACRIFICE AT 104 WEEKS
                                                 FEMALE TERMINAL SACRIFICE AT 105 WEEKS
|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   CONTROL      37.5 PPM     75 PPM       150 PPM   |   CONTROL      37.5 PPM     75 PPM       150 PPM   |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|All Organs                                                                                                                       |
|     Hemangiosarcoma or Hemangioma                                                                                               |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |    #            #            #            #        |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  3/60 (5%)    3/60 (5%)    2/60 (3%)    3/60 (5%)  |  3/60 (5%)    4/60 (7%)    0/59 (0%)    1/60 (2%)  |
|ADJUSTED (b)           |   7.8%         8.3%         5.7%         7.6%      |   8.4%         9.5%         0.0%         2.5%      |
|INTERIM SACRIFICE 1 (c)|  0/10 (0%)    0/10 (0%)    0/10 (0%)    0/7 (0%)   |  0/9 (0%)     0/9 (0%)     0/9 (0%)     0/10 (0%)  |
|TERMINAL (d)           |  2/37 (5%)    2/35 (6%)    2/35 (6%)    0/30 (0%)  |  1/32 (3%)    4/42 (10%)   0/36 (0%)    0/37 (0%)  |
|FIRST INCIDENCE (DAYS) |   604          724          725 (T)      553       |   690          729 (T)      ---          716       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.526      P=0.652      P=0.518N     P=0.609    |  P=0.097N     P=0.633      P=0.112N     P=0.257N   |
|INCIDENTAL TUMOR       |  P=0.478N     P=0.595N     P=0.478N     P=0.443N   |  P=0.136N     P=0.501      P=0.195N     P=0.418N   |
|LOGISTIC REGRESSION    |  P=0.571      P=0.629N     P=0.498N     P=0.652    |  P=0.107N     P=0.580      P=0.120N     P=0.545N   |
|COCHRAN-ARMITAGE       |  P=0.562N                                          |  P=0.112N                                          |
|FISHER EXACT           |               P=0.660N     P=0.500N     P=0.660N   |               P=0.500      P=0.125N     P=0.309N   |
|=================================================================================================================================|
|                                                                                                                                 |
|All Organs                                                                                                                       |
|     Histiocytic Sarcoma                                                                                                         |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |    #            #            #            #        |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  0/60 (0%)    0/60 (0%)    0/60 (0%)    0/60 (0%)  |  2/60 (3%)    2/60 (3%)    0/59 (0%)    2/60 (3%)  |
|ADJUSTED (b)           |   0.0%         0.0%         0.0%         0.0%      |   4.5%         4.8%         0.0%         4.8%      |
|INTERIM SACRIFICE 1 (c)|  0/10 (0%)    0/10 (0%)    0/10 (0%)    0/7 (0%)   |  0/9 (0%)     0/9 (0%)     0/9 (0%)     0/10 (0%)  |
|TERMINAL (d)           |  0/37 (0%)    0/35 (0%)    0/35 (0%)    0/30 (0%)  |  0/32 (0%)    2/42 (5%)    0/36 (0%)    1/37 (3%)  |
|FIRST INCIDENCE (DAYS) |   ---          ---          ---          ---       |   576          729 (T)      ---          485       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |    (e)          (e)          (e)          (e)      |  P=0.553N     P=0.633N     P=0.252N     P=0.686N   |
|INCIDENTAL TUMOR       |    (e)          (e)          (e)          (e)      |  P=0.589N     P=0.499      P=0.327N     P=0.727N   |
|LOGISTIC REGRESSION    |    (e)          (e)          (e)          (e)      |  P=0.556N     P=0.688N     P=0.245N     P=0.537    |
|COCHRAN-ARMITAGE       |    (e)                                             |  P=0.555N                                          |
|FISHER EXACT           |                 (e)          (e)          (e)      |               P=0.691N     P=0.252N     P=0.691N   |
|=================================================================================================================================|
         DATE: 05/20/95                     EXPERIMENT: 05185 TEST: 04                                                 PAGE  15
                           STATISTICAL ANALYSIS OF PRIMARY TUMORS IN MICE(B6C3F1) -- ISOBUTYL NITRITE (IBN)
                                                 MALE TERMINAL SACRIFICE AT 104 WEEKS
                                                 FEMALE TERMINAL SACRIFICE AT 105 WEEKS
|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   CONTROL      37.5 PPM     75 PPM       150 PPM   |   CONTROL      37.5 PPM     75 PPM       150 PPM   |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|All Organs                                                                                                                       |
|     Malignant Lymphoma And Histiocytic Sarcoma                                                                                  |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |    #            #            #            #        |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  1/60 (2%)    3/60 (5%)    2/60 (3%)    2/60 (3%)  |  8/60 (13%)   8/60 (13%)  11/59 (19%)  11/60 (18%) |
|ADJUSTED (b)           |   2.6%         7.7%         5.7%         5.9%      |  19.3%        17.9%        27.6%        25.6%      |
|INTERIM SACRIFICE 1 (c)|  0/10 (0%)    0/10 (0%)    0/10 (0%)    0/7 (0%)   |  0/9 (0%)     0/9 (0%)     0/9 (0%)     0/10 (0%)  |
|TERMINAL (d)           |  0/37 (0%)    2/35 (6%)    2/35 (6%)    1/30 (3%)  |  3/32 (9%)    6/42 (14%)   8/36 (22%)   7/37 (19%) |
|FIRST INCIDENCE (DAYS) |   618          581          725 (T)      625       |   576          520          558          114       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.432      P=0.323      P=0.490      P=0.467    |  P=0.243      P=0.453N     P=0.364      P=0.382    |
|INCIDENTAL TUMOR       |  P=0.581      P=0.205      P=0.541      P=0.612    |  P=0.153      P=0.500      P=0.200      P=0.206    |
|LOGISTIC REGRESSION    |  P=0.473      P=0.314      P=0.504      P=0.703    |  P=0.204      P=0.337      P=0.170      P=0.306    |
|COCHRAN-ARMITAGE       |  P=0.501                                           |  P=0.217                                           |
|FISHER EXACT           |               P=0.309      P=0.500      P=0.500    |               P=0.605N     P=0.295      P=0.309    |
|=================================================================================================================================|
|                                                                                                                                 |
|All Organs                                                                                                                       |
|     Malignant Lymphoma: Histiocytic, Lymphocytic, Mixed, NOS, or Undifferentiated                                               |
|     Cell Type                                                                                                                   |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |    #            #            #            #        |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            |  1/60 (2%)    3/60 (5%)    2/60 (3%)    2/60 (3%)  |  7/60 (12%)   6/60 (10%)  11/59 (19%)   9/60 (15%) |
|ADJUSTED (b)           |   2.6%         7.7%         5.7%         5.9%      |  17.6%        13.3%        27.6%        21.5%      |
|INTERIM SACRIFICE 1 (c)|  0/10 (0%)    0/10 (0%)    0/10 (0%)    0/7 (0%)   |  0/9 (0%)     0/9 (0%)     0/9 (0%)     0/10 (0%)  |
|TERMINAL (d)           |  0/37 (0%)    2/35 (6%)    2/35 (6%)    1/30 (3%)  |  3/32 (9%)    4/42 (10%)   8/36 (22%)   6/37 (16%) |
|FIRST INCIDENCE (DAYS) |   618          581          725 (T)      625       |   585          520          558          114       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.432      P=0.323      P=0.490      P=0.467    |  P=0.277      P=0.367N     P=0.276      P=0.471    |
|INCIDENTAL TUMOR       |  P=0.581      P=0.205      P=0.541      P=0.612    |  P=0.174      P=0.582N     P=0.144      P=0.233    |
|LOGISTIC REGRESSION    |  P=0.473      P=0.314      P=0.504      P=0.703    |  P=0.236      P=0.492      P=0.123      P=0.390    |
|COCHRAN-ARMITAGE       |  P=0.501                                           |  P=0.251                                           |
|FISHER EXACT           |               P=0.309      P=0.500      P=0.500    |               P=0.500N     P=0.210      P=0.395    |
|=================================================================================================================================|
         DATE: 05/20/95                     EXPERIMENT: 05185 TEST: 04                                                 PAGE  16
                           STATISTICAL ANALYSIS OF PRIMARY TUMORS IN MICE(B6C3F1) -- ISOBUTYL NITRITE (IBN)
                                                 MALE TERMINAL SACRIFICE AT 104 WEEKS
                                                 FEMALE TERMINAL SACRIFICE AT 105 WEEKS
|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   CONTROL      37.5 PPM     75 PPM       150 PPM   |   CONTROL      37.5 PPM     75 PPM       150 PPM   |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|All Organs                                                                                                                       |
|     Benign Tumors                                                                                                               |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |    #            #            #            #        |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            | 28/60 (47%)  31/60 (52%)  33/60 (55%)  36/60 (60%) | 28/60 (47%)  38/60 (63%)  31/59 (53%)  35/60 (58%) |
|ADJUSTED (b)           |  61.1%        71.3%        72.5%        81.1%      |  69.3%        82.4%        73.3%        77.5%      |
|INTERIM SACRIFICE 1 (c)|  4/10 (40%)   3/10 (30%)   4/10 (40%)   3/7 (43%)  |  1/9 (11%)    2/9 (22%)    2/9 (22%)    2/10 (20%) |
|TERMINAL (d)           | 20/37 (54%)  23/35 (66%)  23/35 (66%)  22/30 (73%) | 20/32 (63%)  34/42 (81%)  25/36 (69%)  27/37 (73%) |
|FIRST INCIDENCE (DAYS) |   455          457 (I)      457 (I)      296       |   458 (I)      458 (I)      458 (I)      458 (I)   |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.006 **   P=0.302      P=0.184      P=0.013 *  |  P=0.357      P=0.429      P=0.549      P=0.362    |
|INCIDENTAL TUMOR       |  P=0.026 *    P=0.543      P=0.346      P=0.069    |  P=0.162      P=0.124      P=0.305      P=0.086    |
|LOGISTIC REGRESSION    |  P=0.033 *    P=0.457      P=0.254      P=0.058    |  P=0.152      P=0.082      P=0.304      P=0.100    |
|COCHRAN-ARMITAGE       |  P=0.081                                           |  P=0.240                                           |
|FISHER EXACT           |               P=0.358      P=0.233      P=0.100    |               P=0.049 *    P=0.324      P=0.136    |
|=================================================================================================================================|
|                                                                                                                                 |
|All Organs                                                                                                                       |
|     Malignant Tumors                                                                                                            |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |    #            #            #            #        |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            | 17/60 (28%)  19/60 (32%)  22/60 (37%)  17/60 (28%) | 17/60 (28%)  18/60 (30%)  19/59 (32%)  19/60 (32%) |
|ADJUSTED (b)           |  35.2%        42.2%        48.0%        40.5%      |  38.1%        36.9%        45.1%        44.4%      |
|INTERIM SACRIFICE 1 (c)|  1/10 (10%)   1/10 (10%)   1/10 (10%)   0/7 (0%)   |  0/9 (0%)     1/9 (11%)    0/9 (0%)     0/10 (0%)  |
|TERMINAL (d)           |  7/37 (19%)  10/35 (29%)  12/35 (34%)   6/30 (20%) |  6/32 (19%)  12/42 (29%)  14/36 (39%)  14/37 (38%) |
|FIRST INCIDENCE (DAYS) |   455          457 (I)      457 (I)      552       |   572          458 (I)      210          114       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.333      P=0.447      P=0.233      P=0.427    |  P=0.433      P=0.408N     P=0.507      P=0.554    |
|INCIDENTAL TUMOR       |  P=0.345N     P=0.470      P=0.239      P=0.341N   |  P=0.291      P=0.295      P=0.278      P=0.225    |
|LOGISTIC REGRESSION    |  P=0.349N     P=0.444      P=0.325      P=0.355N   |  P=0.349      P=0.184      P=0.403      P=0.409    |
|COCHRAN-ARMITAGE       |  P=0.528N                                          |  P=0.376                                           |
|FISHER EXACT           |               P=0.421      P=0.218      P=0.580N   |               P=0.500      P=0.397      P=0.421    |
|=================================================================================================================================|
         DATE: 05/20/95                     EXPERIMENT: 05185 TEST: 04                                                 PAGE  17
                           STATISTICAL ANALYSIS OF PRIMARY TUMORS IN MICE(B6C3F1) -- ISOBUTYL NITRITE (IBN)
                                                 MALE TERMINAL SACRIFICE AT 104 WEEKS
                                                 FEMALE TERMINAL SACRIFICE AT 105 WEEKS
|=================================================================================================================================|
|                       |                                                    |                                                    |
|                       |                       MALES                        |                      FEMALES                       |
|                       |                                                    |                                                    |
|DOSE                   |   CONTROL      37.5 PPM     75 PPM       150 PPM   |   CONTROL      37.5 PPM     75 PPM       150 PPM   |
|                       |                                                    |                                                    |
|=================================================================================================================================|
|                                                                                                                                 |
|All Organs                                                                                                                       |
|     Malignant and Benign Tumors                                                                                                 |
|                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------|
|TUMOR RATES            |    #            #            #            #        |    #            #            #            #        |
|-----------            |                                                    |                                                    |
|OVERALL (a)            | 38/60 (63%)  39/60 (65%)  43/60 (72%)  42/60 (70%) | 38/60 (63%)  48/60 (80%)  39/59 (66%)  42/60 (70%) |
|ADJUSTED (b)           |  71.4%        80.8%        84.0%        85.6%      |  80.4%        92.2%        84.3%        87.3%      |
|INTERIM SACRIFICE 1 (c)|  5/10 (50%)   4/10 (40%)   5/10 (50%)   3/7 (43%)  |  1/9 (11%)    3/9 (33%)    2/9 (22%)    2/10 (20%) |
|TERMINAL (d)           | 22/37 (59%)  26/35 (74%)  27/35 (77%)  23/30 (77%) | 23/32 (72%)  38/42 (90%)  29/36 (81%)  31/37 (84%) |
|FIRST INCIDENCE (DAYS) |   455          457 (I)      457 (I)      296       |   458 (I)      458 (I)      210          114       |
|-----------------------|                                                    |                                                    |
|STATISTICAL TESTS (f)  |                                                    |                                                    |
|-----------------------|                                                    |                                                    |
|LIFE TABLE             |  P=0.030 *    P=0.463      P=0.219      P=0.073    |  P=0.453N     P=0.535      P=0.442N     P=0.535N   |
|INCIDENTAL TUMOR       |  P=0.145      P=0.565N     P=0.311      P=0.324    |  P=0.325      P=0.028 *    P=0.385      P=0.100    |
|LOGISTIC REGRESSION    |  P=0.096      P=0.570N     P=0.279      P=0.156    |  P=0.346      P=0.014 *    P=0.445      P=0.213    |
|COCHRAN-ARMITAGE       |  P=0.214                                           |  P=0.468                                           |
|FISHER EXACT           |               P=0.500      P=0.218      P=0.281    |               P=0.034 *    P=0.451      P=0.281    |
|=================================================================================================================================|
 (a)  Number of tumor-bearing animals / number of animals examined at site.
 (b)  Kaplan-Meier estimated lifetime tumor incidence after adjustment for 
      intercurrent mortality.
 (c)  Observed incidence at interim kill.
          Male interim sacrifices(days):   457
          Female interim sacrifices(days): 458
 (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).