title: Cancer and developmental exposure to endocrine disruptors.
abstract: Developing organisms have increased susceptibility to cancer if they are exposed to environmental toxicants during rapid growth and differentiation. Human studies have demonstrated clear increases in cancer after prenatal exposure to ionizing radiation, and there is suggestive evidence that brain tumors and leukemia are associated with parental exposures to chemicals. Animal experiments have demonstrated increased tumor formation induced by prenatal or neonatal exposure to a variety of chemicals, including direct-acting carcinogens and drugs. Recently, natural estrogens have been classified as known human carcinogens. Prenatal exposure to natural and synthetic estrogens is associated with increases in breast and vaginal tumors in humans as well as uterine tumors in animals. Synthetic halogenated chemicals increase liver tumors after early life-stage exposure. Recently, a prototypical endocrine-disrupting compound, 2,3,7,8-tetrachlorodibenzo-p-dioxin, has been shown to be a developmental toxicant of the mammary gland in rodents. Dioxin alters multiple endocrine systems, and its effects on the developing breast involve delayed proliferation and differentiation of the mammary gland, as well as an elongation of the window of sensitivity to potential carcinogens. Implications of these new findings suggest that causes of endocrine-related cancers or susceptibility to cancer may be a result of developmental exposures rather than exposures existing at or near the time of tumor detection.
authors.affiliation: Experimental Toxicology Division, National Health and Environmental Effects Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina, USA. birnbaum.linda@epa.gov
authors.forename: Linda S
authors.initials: LS
authors.lastname: Birnbaum
authors.forename: Suzanne E
authors.initials: SE
authors.lastname: Fenton
mesh_terms: D000328:Adult; D000818:Animals; D001280:Atrazine / Q000009:adverse effects; D001943:Breast Neoplasms / Q000209:etiology; D002273:Carcinogens / Q000009:adverse effects*; D002471:Cell Transformation, Neoplastic; D002648:Child; D002657:Child Development; D002675:Child, Preschool; D004147:Dioxins / Q000009:adverse effects; D004195:Disease Models, Animal; D005314:Embryonic and Fetal Development; D004703:Endocrine System / Q000187:drug effects*; D004785:Environmental Pollutants / Q000009:adverse effects*; D005260:Female; D006540:Herbicides / Q000009:adverse effects; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D015674:Mammary Neoplasms, Animal / Q000209:etiology; D009369:Neoplasms / Q000209:etiology*; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D012377:Rodentia; D014625:Vaginal Neoplasms / Q000209:etiology
chemical_list: D002273:Carcinogens; D004147:Dioxins; D004785:Environmental Pollutants; D006540:Herbicides; D001280:Atrazine