Document km3VqEe4Rm7KN4N0rjo9ndwZV

National Cancer Institute CARCSSSSOGE^ESSS Technical Report Series No. 38 1978 U.S. DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE X Public Health Service National Institutes of Health PCB-ARCH-EXT0376664 BIOASSAY OF AROCLOR 1254 FOR POSSIBLE CARCINOGENICITY Carcinogenesis Testing Program Division of Cancer Cause and Prevention National Cancer Institute National Institutes of Health Bethesda, Maryland 20014 U.S. DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE Public Health Service National Institutes of Health DI1EW Publication No. (NIH) 78-838 PCB-ARCH-EXT0376665 bioassay were analyzed at Stanford Research Institute, and the analytical results were reviewed by Dr. C. W. Jameson^.. ' i This report was prepared at Tracor Jitco^ under the direction of NCI. Those responsible for the report at Tracor Jitco were Dr. Marshall Steinberg, Director of the Bioassay Program; Drs. J. F. Robens and R. W. Fogleman, toxicologists; Dr. R. L. Schueler, pathologist; Ms. L. A. Waitz and Mr. W. D. Reichardt, bioscience writers; and Dr. E. W. Gunberg, technical editor, assisted by Ms. Y. E. Presley. The statistical analysis was reviewed by members of the Mathematical Statistics and Applied Mathematics Section of NCI^: Dr. John J. Cart, Mr. Jun-mo Nam, Dr. Hugh M. Pettigrew, and Dr. Robert E. Tarone. The following other scientists at the National Cancer Institute were responsible for evaluating the .bioassay experiment, interpreting the results, and reporting the findings: Dr. Kenneth C. Chu Dr. Cipriano Cueto, Jr. Dr. J. Fielding Douglas Dr. Dawn G. Goodman Dr. Richard A. Griesemer Mr. Harry A. Milman . . Dr. Thomas W. Orme Dr. Robert A. Squire^ Dr. Jerrold M. Ward ^Carcinogenesis Testing Program, Division of Cancer Cause and Prevention, National Cancer Institute, National Institutes of Health, Bethesda, Maryland. ' j ^Now with the Office of the Commissioner, Food and Drug t Administration, Rockville, Maryland. ^Stanford Research Institute, Menlo Park, California. iv PCB-ARCH-EXT0376667 In the stomach, jejunum, or cecum, adenocarcinomas were observed in two dosed males and in two dosed females as well as a carcinoma in one dosed male. None of these lesions was found in control animals in this study. Historical incidences of these tumors at this laboratory (6/600 males [1%], 2/600 females [0.3%] suggest that the lesions -- although not statistically signifi cant -- may be related to the administration of Aroclor 1254. It is concluded that under the conditions of this bioassay, Aroclor 1254 was not carcinogenic in Fischer 344 rats; however, a high incidence of hepatocellular proliferative lesions in both male and female rats was related to administration of the chemical. In addition, the carcinomas of the gastrointestinal tract may be associated with administration of Aroclor 1254 in both males and females. viii I. INTRODUCTION Aroclor (CAS 27323-18-8; NCI C02664) is the registered trademark of the Monsanto Chemical Company for their polychlorinated biphenyls (PCBs). PCBs were developed in 1929 primarily for use as heat transfer fluids and dielectrics (insulators). Aroclor 1254, a biphenyl containing approximately 54% chlorine, is a nonflammable heat transfer agent which functions in the range of 250-360C (Hubbard, 1964; Poffenberger and Hubbard, 1965). PCBs have been used in transformers and capacitors; as industrial fluids in hydraulic, gas turbine, and vacuum pumps; as lubricants and plasticizers (for flame retardation); and as additives in surface coatings, inks, papers, adhesives, sealants, pesticides, and dyes for carbonless duplicating paper (Hubbard, 1964; Broadhurst, 1972). These compounds tend to accummulate in the biosphere (Finklea et al. , 1972). Because of direct and indirect human and animal exposure, food contamination, and environmental pollution from many of these uses, the marketing of PCBs has been markedly curtailed in recent years (EPA, 1977). This bioassay of Aroclor 1254 was conducted as a part of a larger study designed to assess the combined effects of a group of known or suspected carcinogens. Only the results of the study of the administration of Aroclor 1254 are reported herein. 1 PCB-ARCH-EXT0376673 j Rats fed Aroclor 1254 were housed in ' the same room as rats treated with aflatoxin Bj (CAS 1162-65-8), lead (II) acetate (CAS 301-04-2), hexachlorophene (CAS 70-30-4), or dieldrin (CAS 60-57-1) in the feed. E. Subchronic Studies Subchronic feeding studies were conducted with male and female Fischer 344 rats to estimate the maximum tolerated dose of Aroclor 1254, on the basis of which low, mid, and high concentrations (hereinafter referred to as "low doses", "mid doses", and "high doses") were determined for administration in the chronic studies. In the subchronic studies, Aroclor 1254 was added to feed in concentrations of 25, 50, 100, 200, or 400 ppm. Treated and control groups each consisted of 15 male and 15 female rats. The chemical was provided in feed to the treated groups for 8 weeks. The animals receiving 400 ppm were inactive, had occasional diarrhea and tremors, and failed to gain weight. At this dose 4/15 males and 1/15 females died. Enlarged livers were observed on gross examination, and histologically atypical hyperplasia was observed'. At 200 ppm, body weights for both males and females were approximately 70% of those of the controls, and mild hepato cellular pleomorphism was seen histologically in the livers. 6 ' PCB-ARCH-EXT0376677 Rats treated with 25 ppm Aroclor 1254 had enlarged livers, but no evidence of histologic abnormalities. Weight gain in all animals treated at doses lower than 200 ppm was comparable to that in controls, and there was no mortality below 400 ppm. The low, mid, and high doses for the chronic studies were set at 25, 50, and 100 ppm. F. Design of Chronic Studies The design of the chronic studies is shown in table 1. G. Clinical and Pathologic Examinations All animals were observed daily for signs of toxicity and palpated for masses at each weighing. Animals were weighed individually every other week for 12 weeks, and once every fourth week for the remainder of the study. Animals that were moribund at the time of clinical examination were killed and necropsied. The pathologic evaluation consisted of gross examination of major organs and tissues from killed animals and from animals found dead. The following tissues were routinely examined micro scopically from both treated and control animals: lungs and bronchi, spleen, liver, testes, pituitary, kidney, and brain. In addition, sections of stomach, urinary bladder, thyroid, uterus, and ovary were examined in a majority, of the controls; these 7 PCB-ARCH-EXT0376678 Table 1. Design of Aroclor 1254 Chronic Feeding Studies in Rats Sex and Treatment Group Males Matched-Control Low-Dose Mid-Dose High-Dose Females Matched-Control Low-Dose Mid-Dose High-Dose Initial No. of Animals3 Aroclor 1254 in Dietb (ppm) Time on Study Treated0 Untreated (weeks) (weeks) 24 0 105 24 25 . 105 24 50 105 24 100 105 24 0 24 25 24 ' 50 24 100 105 104-105 104-105 105 aAll animals were 53+2 days of age when placed on study. ^All diets contained 3% corn oil. CA11 animals were started on study within 2 days of each other. 8 PCB-ARCH-EXT0376679 "\ tissues were taken from treated rats only if a lesion was found at necropsy. Occasionally, additional tissues were examined microscopically. Gross lesions from all animals were also examined microscopically. The different tissues were preserved in 10% buffered formalin, embedded in paraffin, sectioned, and stained with hematoxylin and eosin. Special staining techniques were utilized when indicated for more definitive diagnosis. A few of the tissues selected by design from some animals were not examined, particularly from those animals that died early. Thus, the number of animals from which particular organs or tissues were microscopically examined varies, and does not necessarily represent the number of animals that were placed on study in each group. H. Data Recording and Statistical Analyses / Pertinent data on this experiment have been recorded in an auto matic data processing system, the Carcinogenesis Bioassay Data System (Linhart et al., 1974). The data elements include descrip tive information on the chemicals, animals, experimental design, clinical observations, survival, body weight, and individual pathologic results, as recommended by the International Union Against Cancer (Berenblum, 1969). Data tables were generated for verification of data transcription and for statistical review. 9 PCB-ARCH-EXT0376680 indicates that there is a theoretical possibility of the induction of tumors by the test chemical, which could not be detected under the conditions of this test. . 14 PCB-ARCH-EXT0376685 III. RESULTS A. Body Weights and Clinical Signs Beginning at about week 10 for the high-dose groups and about . week 20 for the mid-dose groups, mean body weights of both male and female rats fed Aroclor 1254 at the doses used in this bioassay were lower than those of the controls (figure 1). Mean body weights of low-dose males appeared comparable to those of controls throughout the study, while mean body weights of lowdose females were lower during the second year of the study. At week 30, an intercurrent respiratory infection in the colony caused weight loss, but no deaths; animals recovered within 30 days without treatment for the infection. Clinical signs associated with administration of Aroclor 1254 included alopecia, amber-colored urine, facial edema, exoph thalmos, and cyanosis. These signs were apparent among the high-dose groups beginning at week 72 and among the mid-dose groups at week 104 of the study. . . B. Survival The Kaplan and Meier curves estimating the probabilities of survival for male and female rats fed Aroclor 1254 in the diet 15 PCB-ARCH-EXT0376686 M EAN BODY W EIGHT (G) ` 400' 300 200 100- A 0 A 8 0 A @ 0 A 0 0 A 0 0 A o AV A 0 0 A @ 0 A 0 A 08 00 AA 8 00 AA 0 0 A O 8 00 AA aa A Q O Oo AA , MALE RATS MATCHED CONTROL O LOW DOSE Q MID DOSE A HIGH DOSE ~r~ T" I 10 20 30 I 40 -r~ 50 60 70 I 80 ~r~ 80 100 110 TIME ON STUDY (WEEKS) 400- 300- 200- O O P O AV P Q 0 P p X V P O 0 P O 0 P O 0 P O 0 PP oO 00 (A i A A A A A A A A A A A A A A. A A FEMALE RATS 100 O MATCHED CONTROL O LOW DOSE Q MID DOSE A HIGH DOSE . ~T~ --I 10 20 I -r- I 30 40 50 I 60 ~r~ I 70 80 90 I 100 no TIME ON STUDY (WEEKS) Figurel. Growth Curves for Rats Fed Aroclor 1254 in the Diet 16 MEAN BODY W EIGHT (G) PCB-ARCH-EXT0376687 1.00 '.vs.wk'.v.'.v.'.v.w/yA <L i rf i - < > >cDwc >t-- m <mocc MALE RATS 0. MATCHED CONTROL O LOW DOSE 0 MID DOSE A HIGH DOSE U - 6--------------<p----- **--- 1 A'-C***!.............. <i>-- --o . 6-; A-;: ^ j ^--A:-- i . i-s6--: A- ^-i A-: CO A-: AA --1-- If; 45 60 75 TIME ON STUDY (WEEKS) PROBABILITY OF SURVIVAL Figure 2. Survival Curves for Rats Fed Aroclor 1254 in the Diet 17 'PpTr;*T^_'; pi?> 4* jvj*-vWv *** w*r.e: rjjW ' ;iLM;t*:'s PCB-ARCH-EXT0376688 . 4 .j ) J at the doses used in this study, together with those of the controls, are shown in figure 2. For males, the result of the Tarone test for positive doserelated trend in mortality over the period is significant (P < 0.001); 92% of the control, 83% of the low-dose, 58% of the mid-dose, and 46% of the high-dose rats survived to the end of the study. Among females, the Tarone test showed a probability level greater than 0.05. In females, 67% of the control, 79% of the low-dose, 83% of the mid-dose, and 71% of the high-dose rats survived to termination of the study. Sufficient numbers of rats of both sexes were available for meaningful statistical analyses of.the incidences of late-developing tumors. . i C. Pathology Histopathologic findings on neoplasms in rats are summarized in Appendix A, tables A1 and A2; findings on nonneoplastic lesions are summarized in Appendix B, tables Bl and B2. A variety of neoplastic processes were observed in both the control and treated rats, and, with the exception of the liver, ij the incidences of these neoplasms were comparable in the control and treated groups. Interstitial-cell tumors of the testes were present in the majority of control and treated males. The next most frequently observed neoplasm was leukemia of either the 18 PCB-ARCH-EXT0376689 jI . i nodular hyperplasia in both the male and female animals. There was one carcinoma and fpur adenocarcinomas in the gastrointes- l tinal tract of treated rats. These neoplastic lesions are seen only sporadically and at a low incidence in the Fischer 344 rat; ! I in this study no lesions of these types were diagnosed in either ! . ! the male or female controls. ! I . j D. Statistical Analyses of Results Tables Cl and C2 in Appendix C contain the statistical analyses f of the incidences of those primary tumors that occurred in at | . least two animals in one group and with an incidence of at least j I i i 7 5% of one or more treated groups. ' ' In male rats, the results of the Cochran-Armitage test for j positive dose-related trend in the incidences of leukemia and of ; combined leukemia and lymphoma are significant (P = 0.022 and P = ; 0.009, respectively). The corresponding results of the Fisher j exact test, however, are not significant in any treated group i when compared with the controls. There is no other incidence of i j tumors at any specific site in either sex which is statistically i ' significant. A significant Cochran-Armitage trend in the . negative direction is observed in the incidence of interstitial cell tumor of the testis, where the incidence in the controls exceeds those in the mid- and high-dose groups. . 21 ' st? PCB-ARCH-EXT0376692 significant for any of these groups, the occurrence of these lesions cannot clearly be related to the administration of Aroclor 1254. Hepatocellular changes including hyperplastic nodules, adenomas, and carcinomas were found in treated animals, but none of these lesions were found in control animals in this study. Hepato cellular carcinomas were observed in one mid-dose' and two highdose males, and hepatocellular adenomas were observed in one high-dose male, one mid-dose female, and two high-dose females. Nodular hyperplasia was diagnosed with a dose-related frequency in the low-, mid-, and high-dose male and female rats. Although the incidences of the tumors were not significant, the occurrence of these proliferative lesions appeared to be related to treatment. In the stomach, jejunum, or cecum, adenocarcinomas were observed in two treated males and in two treated females as well as a carcinoma in one treated male. None of these lesions was found in control animals in this study, suggesting that the lesions --- although not statistically significant -- may be related to the administration of Aroclor 1254. The toxicity of polychlorinated biphenyls (PCBs) has been reviewed by several groups, including the Environmental 24 PCB-ARCH-EXT0376695 V. BIBLIOGRAPHY Armitage, P. , Statistical Methods in Medical Research, John Wiley & Sons, Inc., New York, 1971, pp. 362-365. Berenblum, I., ed. , Carcinogenicity Testing: A Report of the ' Panel on Carcinogenicity of the Cancer Research Commission of the UICC, Vol. 2. International Union Against Cancer, Geneva, 1969. . Broadhurst, M. G. , Use and replaceability of polychlorinated biphenyls. Environ. Health Perspect. 2:81-102, 1972. Cox, D. R., Regression models and life tables, Jj^ R^_ Statist. Soc. B34(2):187-220, 1972. " Cox, D. R. , Analysis of Binary Data, Methuen & Co., Ltd., London, 1970, pp. 48-52.' Environmental Protection Agency, Polychlorinated Biphenyls (PCBs). Toxic Substances Control. Federal Register 42(100), 26564-26577, 1977. ' ...................... ... Environmental Protection Agency, Criteria Document PCBs, U. S. Government Printing Office, Washington, D. C., 440/9-76-021. Finklea, J., Hinners, residues problem. Priester, L. E., Creason, J. P., Hauser, T., T., and Hammer, D. I., Polychlorinated biphenyl in human plasma expose a major' urban pollution AJPH 62(5):645-651, 1972. Gart, J. J., The. comparison' of proportions: a review of significance tests, confidence limits and adjustments for stratification. Rev. Int. Stat. Inst. 39(2):148-169, 1971- Hubbard, H. L., Chlorinated biphenyl and related compounds. Kirk-0thmer Encyclopedia of Chemical Technology. Vol. j). Interscience Publishers, New York, 1964, pp. 289-297. International Agency for Research on Cancer, Some anti-thyroid and related substances, nitrofurans and industrial chemicals. IARC Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to Man; Vol. _7, World Health Organization, Geneva, 1974, pp. 261-289. 27 PCB-ARCH-EXT0376698 Panel on Hazardous Trace Substances, Polychlorinated biophenyls-environmental impact. Environ. Res. _5:249-362, 1972. ' .......... ..... ..................... . ' Poffenberger, N. and Hubbard, H. L. , Diphenyl and terphenyls. Kirk-Othmer Encyclopedia of Chemical Technology, Vol. _1, Interscience Publishers, New York, 1965, p. 193. Saffiotti, U., Montesano, R. , Sellakumar, A. R. , Cefis, F., and Kaufman, D. G. , Respiratory tract carcinogenesis in hamsters induced by different numbers of administrations of benzo(a) pyrene and ferric oxide. Cancer Res 32:1073-1081, 1972. Squire, R. A. and Levitt, M. H., Report on a workshop on classification of specific heptocellular lesions in rats. Cancer Res. 35:3214-3223, 1975. Tarone, R. E., Tests for trend in life table analysis. Biometrika 62(3):679-682, 1975. 29 PCB-ARCH-EXT0376700 TABLE A1. MALE RATS: NEOPLASMS (CONTINUED) CONTROL LOW DOSE MID DOSE HIGH DOSE SPECIAL SENSE ORGANS NONE MUSCULOSKELETAL STSTEH NONE BODY CAVITIES TUNICA VAGINALIS MESOTHELIOMA, MALIGNANT ALL OTHER SYSTEMS NONE (24) 1 (4%) (24) (2 4) (24) ANIMAL DISPOSITION SUMMARY ANIMALS INITIALLY IN STUDY 24 24 NATURAL DEATHS 2 MORIBUND SACRIFICE 4 SCHEDULED SACRIFICE . ACCIDENTALLY KILLED TERMINAL SACRIFICE 22 20 ` ANIMAL MISSING 3 INCLUDES AU1CLYZED ANIMALS # NUMBER OF ANIMALS WITH-TISSUE EXAMINED MICROSCOPICALLY * NUMBER OF ANIMALS NECROPSIED # 1 24 3 7 14 24 1 12 11 \ i 35 PCB-ARCH-EXT0376704 TABLE A1. MALE RATS: NEOPLASMS (CONTINUED) CONTROL LOW DOSE MID DOSE HIGH DOSE TUtlOR SUMMARY TOTAL ANIMALS WITH PRIMARY TUMORS* TOTAL PRIMARY TUMORS 24 32 24 32 20 32 TOTAL ANIMALS WITH BENIGN TUMORS 24 TOTAL BENIGN TUMORS .. 27 24 30 20 ` 23 TOTAL ANIMALS WITH MALIGNANT TUMORS 5 TOTAL MALIGNANT TUMORS 5 2- 9. 2 9 TOTAL ANIMALS WITH SECONDARY TUMORS# 1 TOTAL SECONDARY TUMORS 1 TOTAL ANIMALS WITH TUMORS UNCERTAIN- BENIGN OR MALIGNANT TOTAL UNCERTAIN TUMORS TOTAL ANIMALS WITH TUMORS UNCERTAIN PRIMARY OR METASTATIC TOTAL UNCERTAIN TUMORS * PRIMARY TUMORS: ALL TUMORS EXCEPT SECONDARY TUMORS # SECONDARY TUMORS: METASTATIC TUMORS OR TUMORS.INVASIVE INTO AN ADJACENT ORGAN 21 37 20 23 12 14 36 TABLE A2. FEMALE RATS: NEOPLASMS (CONTINUED) CONTROL ' LOW DOSE MID DOSE HIGH DOSE DIGESTIVE SYSTEM LIVER UNDIFFERENTIATED CARCINOMA HETAS ADENOMA, NCS STOMACH ADENOMA, NCS ADENOCARCINOMA, NOS ^ (23) (21) (24) 1 (4%) (3) 1 (33*) URINARY SYSTEM GENITOURINARY TRACT LIPCMA KIDNEY UNDIFFERENTIATED CARCINOMA ENDOCRINE SYSTEM PITUITARY ADENOMA, NOS (24) (23) l (23) 4 (17*) (24) 1 (4%) (24) . 1 (4%) (22) 1 (5*) REPRODUCTIVE SYSTEM MAMMARY GLANE ADENOMA, NCS ADENOCARCINOMA, NOS UTERUS ' ADENOCARCINOMA, NOS ADENOCA IN ADENOMATOUS POLYP LEIOMYOMA ENDOMETRIAL STROMAL POLYP OVARY GRANULOSA-CELL TUMOR (24) 1 (4*) (14) 2 (14*) (20) (24) 4 (17*) (12) 1 (8*) 1 (8*) 5 (42*) (D 1 (100%) NERVOUS SYSTEM NONE # NUHBER OF ANIMALS WITH TISSUE EXAHINED MICROSCOPICALLY * NUMBER OF ANIMALS NECROPSIFD ( (22) 1 (5S) (D 1 (100*) (24) 2 (8%) (6) 1 (17*) (24) (24) (24) (23) (22) 1 (5*) (23) . 1 (4X) (24) (15) E (33*) <3) (24) (6) 1 (17%) 1 (17*) 3 (50%) 38 PCB-ARCH-EXT0376707 I ; TABLE A2. FEMALE RATS: NEOPLASMS (CONTINUED) i \ CONTROL LOW DOSE MID DOSE HIGH DOSE ii ------------------------------------------------------------------------ } SPECIAL SENSE ORGANS ( | *EYE (24) (24) (24) (24) | SEBACEOUS ADENOCARCINOMA 1 (4S) | MUSCULOSKELETAL SYSTEM j NONE 1 BODY CAVITIES j NONE : ALL OTHER SYSTEMS ? NONE r ANIMAL DISEOSITIO N SUMMARY \ ANIMALS INITIALLY IN STUDY NATURAL DEATHS MORIBUND SACRIFICE SCHEDULED SACRIFICE ACCIDENTALLY KILLED TERMINAL SACRIFICE ANIMAL MISSING 24 1 7 16 24 1 19 24 1 3 . 2C 24 7 17 3 INCLUDES ADTOLYZED ANIMALS * NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY * NUMBER OF ANIMALS NECROPSIED ij\ ( ll \ \ 39 PCB-ARCH-EXT0376708 APPENDIX B SUMMARY OF THE INCIDENCE OF NONNEOPLASTIC LESIONS ! ` i IN RATS FED AROCLOR1254 IN THE DIET ; I [ f is I: ti'. fi 41 PCB-ARCH-EXT0376710 TABLE B1 SUMMARY OF THE IMCiDEWCE OF NONNEOPLASTIC LESIONS IN MALE RATS FED AROCLOR 1254 IN THE DIET* CONTROL ANIMALS INITIALLY IN STDDY 2D ANIMALS NECROPSIED 24 ANIMALS EXAMINED DISTOPATHOLOGICALLY 24 LOW DOSE 24 ' 24 24 MID DOSE 24 24 24 INTEGUMENTARY SYSTEM ' ^ *SOBCOT TISSUE CYST, NOS (24) 1 (456) (24) (24) RESPIRATORY SYSTEM TRACHEA INFLAMMATION, NOS #LUNG/BRONCHUS BRONCHIECTASIS INFLAM MATIC N, NOS LUNG EMPHYSEMA, NOS ATELECTASIS CONGESTION, NOS INFLAMMATICN, NOS ABSCESS, NOS (19) 1 (5%) (23) 1 (4 56) (23) . 1 (4%) 9 (3956) 2 (9%) (24) 4 ( 1755) 1 (4%) (24) 1 (45!) 12 (50%) 2 (8%) (D (23) 7 (3056) (23) 2 (936) 7 (3056) 3 (1 356) HEMATOPOIETIC SYSTEM SPLEEN CONGESTION, NOS FIBROSIS HEMATOPOIESIS (23) 1 (456) (24) 2 (856) 1 (456) LYMPH NODE CONGESTION, NOS NECROSIS, NOS HYPERPLASIA, NOS HISTIOCYTOSIS (3) (3) 2 (6755) * NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY * NUMBER OF ANIMALS NECROPSIED (23) 1 (4%) 2 (95!) (4) 1 (2516) 1 (2556) HIGH DOSE 24 24 24 (24) (24) 1 (456) (24) 1 (456) 4 (1756) 1 (456) 2 (8%) . (24) (5) 1 (2056) 43 PCB-ARCH-EXT0376711 1 I TABLE B1. MALE RATS: NONNEOPLASTIC LESSONS (CONTINUED) CONTROL LOW DOSE MID DOSE ' CELIAC LYMPH NODE LYMPHANGIECTASIS (3) (3) (<l) CIRCULATORY SYSTEM NONE ~ DIGESTIVE SYSTEM SALIVARY GLAND INFLAMMATION, NOS LIVER CONGESTION, NOS INFLAMMATION, GRANULOMATOUS GRANULOMA, NOS NECROSIS, NOS NECROSIS, FOCAL NECROSIS, CENTRAL HYPERPLASIA, NODULAR ANGIECTASIS STOMACH DIVERTICULUM HYPERPLASIA, LYMPHOID tGASTRIC MUCOSA CONGESTION, NOS HYPERPLASIA, NOS COLON FIBROSIS ' . PIGMENTATION, NOS CECUM NECROSIS, NOS (24) 10 (42?) 4 (17?) (21) 1 (5?) (21) (D 1 (100?) (24) 18 (75?) 1 (4?) 5 (21?) (3) (24) 10 (42?) 1 (4?) 8 (33?) 2 (8?) (2) (2) 1 (50?) (1) (1) URINARY SYSTEM KIDNEY (24) (24) (24) _____ CYSTj__NOS_______________________ _______________________ ____________________2__(8%)__________________ L * NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY * NUMBER OF ANIMALS NECROPSIED HIGH DOSE (5) .1 (20?) (24) 4 (17?) 1 (4?) 1 (4?) 1 (4?) 2 (8?) 1 (4?) 12 (50?) (6) 1 (17?) (6) 1 (17?) i 2 (33?) (4) 1 (25?) 1 (25?) (4) 1 (25?) (24) 44 rr* PCB-ARCH-EXT0376712 TABLE B1. MALE RATS: NONNEGPLASTIC LESIONS (CONTINUED) PYELON EFHEITIS, NOS SCLEROSIS CONTROL LOW b0SE 1 (NS) 1 (NS) ENDOCRINE SYSTEM . PITUITARY CYST, NOS CONGESTION, NOS PARATHYROID HYPERPLASIA, NOS (23) 1 (4*) (3) 1 (3356) (2N) 1 (NS) REPRODUCTIVE SYSTEM NONE NERVOUS SYSTEM BRAIN CONGESTION, NOS . EDEMA, NOS ABSCESS, NOS INFARCT, NCS (23) (2) 1 (NS) SPECIAL SENSE ORGANS NONE MUSCULOSKELETAL SYSTEM NONE BODY CAVITIES INGUINAL REGION NECROSIS, EAT (2N) 6 (25S) (2N) 5 (21S) ALL OTHER SYSTEMS _N21! NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY * NUMBER OF ANIMALS NECROPSIED MID DOSE HIGH DOSE (22) 1 (5S) (1) (2N) 2 (8S) (2N) 1 (4S) 1 (4S) 1 (NS) (24) 1 (456) (2N) 2 (13S) (2N) N (17S) 45 PCB-ARCH-EXT0376713 11 TABLE B1. MALE RATS: NONNEOPLASTIC LESIONS (CONTINUED) CONTROL LOW DOSE SPECIAL MORPHOLOGY SUMMARY NONE * NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY * NUMBER OF ANIMALS NECROPSIED MID DOSE HIGH DOSE I ' |i 46 PCB-ARCH-EXT0376714 . /? ' 5! 1 TABLE B2. FEMALE RATS: NONNEOPLASTIC LESIONS (CONTINUED) h CONTROL LOW DOSE MID DOSE HIGH DOSE MUSCULOSKELETAL SYSTEM $ NONE ''k % BODY CAVITIES INGUINAL REGION LIPOGRANULCMA (24) (24) 1 <4X) (24) (24) ALL OTHER SYSTEMS - -j NONE s SPECIAL MORPHOLOGY SUMMARY > NO LESION REPORTED 1 < NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY * NUMBER OF ANIMALS NECROPSIED -J ! l r\ iI 50 PCB-ARCH-EXT0376718 Table C2. Analyses of the Incidence of Primary Tumors in Female Rats Fed Aroclor 1254 in the Diet3 Topography: Morphology , Hematopoietic System: Leukemia*5 P Values0'^ Relative Risk (Matched Control)f Lower Limit Upper Limit Weeks to First Observed Tumor Hematopoietic System: Lymphoma or Leukemia*5 P Values0'^ Relative Risk (Matched Control)f Lower Limit Upper Limit Weeks to First Observed Tumor Matched Control 4/24 (17) N.S. 81 4/24 (17) N.S. 81 Low Dose 6/24 (25) N.S. 1.500 0.411 6.316 74 6/24 (25) N.S. 1.500 0.411 6.316 74 Mid Dose High Dose 6/24 (25) N.S. 1.500. 0.411 6.316 99 4/24 (17) . N.S. 1.000 0.211 4.754 84 6/24 (25) N.S. 1.500 0.411 6.316 99 6/24 (25) N.S. 1.500 0.411 6.316 84 Table C2. Analyses of the Incidence of Primary Tumors in Female Rats Fed Aroclor 1254 in the Diet3 (continued) Tonography: Morphology Matched Control Low Dose Mid Dose High Dose Pituitary: Adenoma, NOS*3 4/24. (17) 1/24 (4) 1/24 (4) 1/24 (4) P Values0 N S. N.S. . N.S. . N.S. Relative Risk (Matched Control)*1 Lower Limit Upper Limit 0.250 0.005 2.288 0.250 0.005 2.288 0.250 0.005 2.288 Weeks to First Observed Tumor 100 105 105 103 Liver: Adenoma, NO s'3 0/24 (0) 0/24 (0) Ui 00 P Values0'11* 11 N.S. N.S. Relative Risk (i&atched Control)f --- * Lower Limit -- Upper Limit ' --_ 1/24 (4) N.S. Infinite 0.055 Infinite 2/24 (8) N.S. Infinite 0.305 Infinite Weeks to First Observed Tumor -- -- .- 105 105 x 3 Table C2. Analyses of the Incidence of Primary Tumors in Female Rats Fed Aroclor 1254 in the Dieta (continued) Topography: Morphology Mammary Gland: Adenocarcinoma, NOS*3 Matched Control 0/24 (0) Low Dose ' h/2h (17) Mid Dose 0/24 (0) High Dose 0/24 (0) P Valuesc>^ N.S. N.S. N.S. N.S. Departure from Linear Trende Relative Risk (Matched Control)^ Lower Limit Upper Limit Weeks to First .Observed Tumor P - 0.003 __ . Infinite 0.961 Infinite 105 ' __ --- -- __ ___ -- .-- __ Mammary Gland': Adenoma or Adenocarcinoma, NOS*3 . 1/24 (4) 4/24 (17) 0/24 (0) 0/24 (0) P Values0'^ . N.S. N.S. ' N.S. N.S. Departure from Linear Trende P = 0.031 Relative Risk (Matched Control)^ ' ' ' Lower Limit Upper Limit .4.000 0.437 187.475 0.000 0.000 18.289 0.000 0.000 . 18.289 Weeks to First Observed Tumor 105 105 -------- -- Table C2. Analyses of the Incidence of Primary Tumors in Female Rats Fed Aroclor 1254 in the Dieta Topography: Morphology Matched Control Low Dose Mid Dose High Dose Uterus: Endometrial Stromal Polypi P Valuesc,c^ 2/24 (8) N.S. 5/24 (21) ' N.S. 5/24 (21) N.S. 3/24 (13) N.S. Relative Risk (Matched Control)^ Lower Limit Upper Limit Weeks to First Observed Tumor 105 2.500 0.459 24.045 100 2.500 0.459 24.045 103 1.500 0.188 16.583 96 O' aTreated groups received doses of 25, 50, or 100 ppm. o ^Number of tumor-bearing animals/number of animals necropsied (percent). cBeneath the incidence of tumors in the control group is the probability level for the CochranArmitage test when P < 0.05; otherwise, not significant (N.S.) is indicated. Beneath the inci dence of tumors in a treated group is the probability level for the Fisher exact test for the comparison of that treated group with the matched-control group when P < 0.05; otherwise, not significant (N.S.) is'indicated. ' 1A negative trend (N) indicates a lower incidence in a treated group than in the control group. eThe probability level for departure from linear trend is given when P < 0.05 for any comparison. ^The 95% confidence interval of the relative risk between each treated group and the matched- control group. Review of the Bioassay of Aroclor 12-5*1* for Carcinogenicity by the Data Evaluation/Risk Assessment Subgroup of the Clearinghouse on Environmental Carcinogens November 28, 1977 The Clearinghouse on Environmental Carcinogens was established in May, 1976 under the authority of the National Cancer Act of 1971 (P.L. 92-218). The purpose of the Clear inghouse is to advise on the National Cancer Institute's bioassay program to identify and evaluate chemical carcinogens in the environment to which humans may be exposed. The members of the Clearinghouse have been drawn from academia, industry, organized labor, public interest groups. State health officials, and quasi-public health and research organizations. Members have been selected on the basis of their experience in carcinogenesis or related fields and, collectively, provide expertise in organic chemistry, bio chemistry, biostatistics, toxicology,'pathology, and epidemiology. Representatives of various Governmental agencies participate as ad hoc members. The Data Evaluation/Risk Assessment ' Subgroup of the Clearinghouse is charged with the responsibility of providing a. peer review of NCI bioassay reports on chemicals studied for carcinogenicity. In this context, below is the edited excerpt from the minutes of the Subgroup's meeting at which Aroclor 125*1 was reviewed. (Aroclor 125*1 was tested in rats as part of another study designed to investigate the combined effects of chemicals.) The primary reviewer briefly outlined the experimental design and findings. Although statistically significant increases in the incidence of tumors were not found in the treated rats, a high incidence of liver hyperplastic nodules was observed in both sexes. The primary reviewer said that in published rat and mouse studies, Aroclor was reported to induce liver neoplasms, although in one rat study only, hyperplastic nodules of the liver were found. In regard to the rat pathology, he said that after the proliferative stimulus is removed, the hyperplastic nodules regress and disappear. Stimuli of such liver nodules act more like tumor promoters than complete carcinogens. Based on reports in the literature, he concluded that Aroclor 125*1 could pose a risk to the human population as a tumor promotor. A lengthy discussion followed as to whether the evidence was adequate to assess Aroclor's tumor promoting potential. . An NCI staff pathologist pointed out that a number of tumors also were found in the gastrointestinal tract of the treated rats. Although they did not occur in statistically significant numbers, none was observed among the control 61 'rvnyr? PCB-ARCH-EXT0376728 animals. A discussion ensued as to the appropriateness of combining tumors when they occur at different sites along the GI tract. , One Subgroup member opined that the study was deficient because of an inadequate number of animals per group. He suggested that the tumors of questionable significance may have been more meaningful had more animals been used. A motion was made that the conclusion stated in the report summary be accepted with an addition that Aroclor 125^ may act as a tumor promoter. The motion thus read: It is concluded that, under the conditions of the bioassay, Aroclor 125^ was not carcinogenic in Fischer 3^ rats; however, a high incidence of hepatocellular proliferative lesions in both male and female rats, was related to treatment. In addition, the carcinomas of the gastrointestinal tract may be associated with treatment in both males and females. Based on the liver proliferative lesions in the treated rats and published reports, it is suggested that Aroclor 125^ may be a tumor promoter. The motion was seconded and accepted by Drs. Wogan, Pitot, Roush, Shimkin, Strong, and Weisburger. Mr. Garfinkel opposed the motion and Dr. Rowe abstained. * Subsequent to this review, changes may have been made in the bioassay report either as a result of the review or other reasons. Thus, certain comments and criticisms reflected in the review may no longer be appropriate. i 1 U.S, GOVERNMENT PAINTING OFFICE: 1978 260-899/3021 1-3 62 ] PCB-ARCH-EXT0376729