Pathology of chronic polychlorinated biphenyl (PCB) feeding in rats

Schaeffer, Ekkehard H.; Greim, Helmut; Goessner, W.

doi:10.1016/0041-008x(84)90210-2

Cited by 71 publications

(36 citation statements)

References 17 publications

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“…For example, Kimura and Baba (1973) suggested that rats exposed to Kanechlor 400 in their diet for over a year had reduced resistance to infection. Schaeffer et al (1984) observed that Wistar rats fed Clophens in their diet for approximately two years experienced fewer deaths from thymomas, Wistar nephritis, and purulent inflammatory lesions of the urogenital system. All of these effects are indicative of a suppressed immune system.…”

Section: Observations That May Indicate Nhlmentioning

confidence: 99%

Methodological Limitations May Prevent the Observation of Non-Hodgkin’s Lymphoma in Bioassays of Polychlorinated Biphenyls

Strauss

Heiger-Bernays

2012

Toxicol Pathol

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Epidemiological studies increasingly indicate that polychlorinated biphenyls (PCBs) contribute to the risk of non-Hodgkin's lymphoma (NHL). In rodent bioassays, PCBs have long been demonstrated to be liver carcinogens, and excess tumors in the thyroid, lung, and other organs have been observed in more recent studies. Leukemias and lymphomas now classified as NHL were observed in one bioassay in which a concurrent infection was also reported. Clinical and epidemiological studies show immunosuppression and inflammation are strong risk factors for NHL, and both epidemiology and toxicology studies show that PCBs are immunosuppressive and cause inflammation. We reviewed published carcinogenesis bioassays conducted using commercial PCB products, individual congeners, and congener mixtures, with a focus on bioassay protocols and immune-related observations. Based on a mode-of-action framework for PCBs, we suggest that an immune challenge in conjunction with PCB exposure may be necessary for the observation of NHL. We conclude that the lack of concordance between human epidemiology and animal bioassays with respect to NHL may simply be the result of the bioassay methodology used, and not a difference in underlying biology. The lack of concordance should not be construed as evidence that PCBs do not contribute to the risk of NHL.

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Section: Observations That May Indicate Nhlmentioning

confidence: 99%

Methodological Limitations May Prevent the Observation of Non-Hodgkin’s Lymphoma in Bioassays of Polychlorinated Biphenyls

Strauss

Heiger-Bernays

2012

Toxicol Pathol

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“…Four studies report that Aroclor 1260 induces hepatocellular carcinomas in laboratory mice and rats exposed to large doses over a lifetime (16)(17)(18)(19). A reevaluation of published studies (20) using uniform pathologic criteria indicates that the potency of the PCB mixtures depends on the chlorination, and not all exposures should be considered equivalent.…”

Section: Polychlorinated Biphenylsmentioning

confidence: 99%

Understanding Population and Individual Risk Assessment: The Case of Polychlorinated Biphenyls

Shields

2006

Cancer Epidemiology, Biomarkers &Amp; Prevention

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Decisions about how to improve or protect the public health can be, and sometimes necessarily are, made on imprecise science. The regulation of potential human carcinogens in the environment entails a population-risk assessment process intended to reduce risks to less than one additional cancer in 100,000 or 1,000,000 persons. These risk assessment processes, however, may be miscommunicated or misinterpreted in the context of individual cancer risks by scientists, regulators, the lay media, and the public. This commentary will review methods for establishing a causal relationship between carcinogen exposures and cancer risk. It will use the case of polychlorinated biphenyls (PCB) as an example of how to place scientific data into the context of human exposure and cancer risk. PCBs are widespread environmental contaminants and most people have detectable levels of PCBs in their bodies. The primary source for exposure in the general population is through the diet. PCBs are carcinogens in experimental animal models, but how this information can be extrapolated to human risk remains uncertain. PCB experimental studies provide data that are used to regulate and control human exposure, although the epidemiologic evidence fails to establish PCBs as human carcinogens. Thus, what is used for populationrisk assessment may not be appropriate for individual-risk assessment or concluding that a causal relationship exists between PCB exposure and cancer risk. The hazards from a carcinogen designated by regulatory and review agencies as a ''probable'' human carcinogen is often misunderstood out of context about the magnitude of the risk and in what settings. How scientists communicate their results in scientific articles can strongly influence how others interpret their data. Misunderstandings from both the use of regulatory and review-agency opinions and the conclusions espoused by scientists occur in the media, among private physicians counseling their patients about cancer risk, and in the legal settings where plaintiffs seek compensation for exposure and alleged harm (or future harm). This can lead to false conclusions about what caused a cancer in a specific patient, undue anxiety about future cancer risk, inappropriate cancer screening, and attendant increased morbidity due to increased uses of the medical system and complication rates from medical procedures. The communication of research findings by scientists must be presented with caution, resisting the temptation to extrapolate, inappropriately, research data to the general population. (Cancer Epidemiol Biomarkers Prev 2006;15(5):830 -9)

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“…Male weanling Wistar rats were fed a diet supplemented with Clophen A 30 (42% chlorine by weight) or Clophen A 60 (60% chlorine by weight) at a concentration of 100 ppm, or an estimated dose of 5 mg/kg bw per day, for up to 832 days; controls were fed the basal diet (Schaeffer et al, 1984;Young, 1985;. Tumour incidence was investigated at intervals of 100 days.…”

Section: Ratmentioning

confidence: 99%

Polychlorinated Biphenyls and Polybrominated Biphenyls

Agudo

Aronson²,

Bonefeld-Jörgensen³

et al. 2008

Organic Pollutants

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initiated a programme on the evaluation of the carcinogenic risk of chemicals to humans involving the production of critically evaluated monographs on individual chemicals. The programme was subsequently expanded to include evaluations of carcinogenic risks associated with exposures to complex mixtures, lifestyle factors and biological and physical agents, as well as those in specific occupations. The objective of the programme is to elaborate and publish in the form of monographs critical reviews of data on carcinogenicity for agents to which humans are known to be exposed and on specific exposure situations; to evaluate these data in terms of human risk with the help of international working groups of experts in carcinogenesis and related fields; and to indicate where additional research efforts are needed. The lists of IARC evaluations are regularly updated and are available on the Internet at http:// monographs.iarc.fr/.This programme has been supported since 1982 by Cooperative Agreement U01 CA33193 with the United States National Cancer Institute, Department of Health and Human Services. Additional support has been provided since 1986 by the European Commission Directorate-General for Employment, Social Affairs, and Inclusion, initially by the Unit of Health, Safety and Hygiene at Work, and since 2014 by the European Union Programme for Employment and Social Innovation "EaSI" (2014-2020) The International Agency for Research on Cancer welcomes requests for permission to reproduce or translate its publications, in part or in full. Requests for permission to reproduce or translate IARC publications -whether for sale or for non-commercial distribution -should be addressed to the IARC Communications Group at: publications@iarc.fr.The designations employed and the presentation of the material in this publication do not imply the expression of any opinion whatsoever on the part of the Secretariat of the World Health Organization concerning the legal status of any country, territory, city, or area or of its authorities, or concerning the delimitation of its frontiers or boundaries.The mention of specific companies or of certain manufacturers' products does not imply that they are endorsed or recommended by the World Health Organization in preference to others of a similar nature that are not mentioned. Errors and omissions excepted, the names of proprietary products are distinguished by initial capital letters.The IARC Monographs Working Group alone is responsible for the views expressed in this publication. IARC Library Cataloguing in Publication Data NOTE TO THE READERThe term 'carcinogenic risk' in the IARC Monographs series is taken to mean that an agent is capable of causing cancer. The Monographs evaluate cancer hazards, despite the historical presence of the word 'risks' in the title.Inclusion of an agent in the Monographs does not imply that it is a carcinogen, only that the published data have been examined. Equally, the fact that an agent has not yet been evaluated in a Monograph does not mean that...

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Pathology of chronic polychlorinated biphenyl (PCB) feeding in rats

Cited by 71 publications

References 17 publications

Methodological Limitations May Prevent the Observation of Non-Hodgkin’s Lymphoma in Bioassays of Polychlorinated Biphenyls

Methodological Limitations May Prevent the Observation of Non-Hodgkin’s Lymphoma in Bioassays of Polychlorinated Biphenyls

Understanding Population and Individual Risk Assessment: The Case of Polychlorinated Biphenyls

Polychlorinated Biphenyls and Polybrominated Biphenyls

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