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According to a comprehensive review of environmental exposures and breast cancer risk, many of the more than 200 chemical compounds found to increase breast tumors in animals are common environmental exposures. These results were published in the journal Cancer.

Breast cancer is diagnosed in more than 178,000 U.S. women each year. Identifying breast cancer risk factors-particularly risk factors that can be modified, such as diet, physical activity, or environmental exposures-is an important focus of breast cancer research. Understanding the factors that contribute to the development of breast cancer is a vital part of identifying approaches to prevention.

To improve our understanding of the role of environmental exposures in breast cancer risk, a review commissioned by Susan G. Komen for the Cure and conducted by researchers at the Silent Spring Institute and other institutions compiled the available evidence from previously published studies.

Animal studies revealed 216 compounds that could potentially play a role in causing breast tumors, including industrial chemicals, chlorinated solvents, products of combustion, pesticides, dyes, radiation, drinking water disinfection byproducts, pharmaceuticals and hormones, natural products, and research chemicals.[[1]]( "_ednref1") Of these,

  • 73 have been present in consumer products or as contaminants in food
  • 35 are air pollutants
  • 25 are occupational exposures that affect more than 5,000 women per year
  • 29 are produced in the U.S. in large amounts

Based on the limited available evidence in humans, environmental pollutants that may increase the risk of breast cancer include polychlorinated biphenols (PCBs-now banned but used previously in electronic equipment), polycyclic aromatic hydrocarbons (PAHs-present in vehicle exhaust), organic solvents, and dioxin.[[2]]( "_ednref2") Other compounds may increase risk in humans as well, but many of the compounds that have been found to increase risk in animals have not been studied in humans.

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The information collected by these reviews will serve as an important resource for scientists, and will help guide future research into environmental risk factors for breast cancer.


[[1]]( "_edn1") Rudel RA, Attfield KR, Schifano JN, Brody JG. Chemicals causing mammary gland tumors in animals signal new directions for epidemiology, chemicals testing, and risk assessment for breast cancer prevention. Cancer [early online publication]. May 14, 2007.

[[2]]( "_edn2") Brody JG, Moysich KB, Humblet O et al. Environmental pollutants and breast cancer: epidemiologic studies. Cancer [early online publication]. May 14, 2007.

Related News:Pesticides May Increase Risk of Breast Cancer (3/19/2007)

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