A new study showed that several common chemicals, including pesticides, ingredients in consumer products, food additives, and drinking water contaminants, could increase breast cancer risk by causing cells in breast tissue to make more hormones, estrogen or progesterone. The results of the study have been published in the journal “Environmental Health Perspectives”.
Every day, people are exposed to a wide variety of synthetic chemicals from the products or foods they use. For many of these chemicals, the health effects are unknown. However, this study found the adverse effects of these chemicals and how they can increase breast cancer risk. “The link between estrogen and progesterone and breast cancer is well established,” said co-author Ruthann Rudel, toxicologist and director of research at the Silent Spring Institute.
“That’s why we should be extremely careful with chemicals in products that increase the levels of these hormones in the body,” added Rudel. For example, when the 2002 Women’s Health Initiative study found that combined hormone replacement therapy was linked to an increased risk of breast cancer, women stopped taking the medication and incidence rates fell.
“Unsurprisingly, one of the most common therapies for treating breast cancer is a class of drugs called aromatase inhibitors, which lower the levels of estrogen in the body and deprive breast cancer cells of the hormones they need to grow,” said Rudel. To identify these chemical risk factors, Rudel and Silent Spring scientist Bethsaida Cardona combed data on more than 2,000 chemicals generated in the EPA’s ToxCast program.
The goal of ToxCast is to improve the ability of scientists to predict whether or not a chemical is harmful. The program uses automated chemical screening technologies to expose living cells to chemicals and then study the various biological changes they cause. In a report in the journal Environmental Health Perspectives, Rudel and Cardona identified 296 chemicals that were used in the laboratory to increase estradiol (a form of estrogen) or progesterone in cells.
71 chemicals were found to increase levels of both hormones. Chemicals included ingredients in personal care products such as hair dyes, chemical flame retardants in building materials and furnishings, and a range of pesticides. Researchers don’t yet know how these chemicals make cells produce more hormones. It could be that the chemicals act as aromatase activators, for example, which would lead to higher levels of estrogen, Cardona said. “What we do know is that women are exposed to multiple chemicals from different sources every day, and those exposures add up.”
The Silent Spring researchers hope this study will be a wake-up call for regulators and manufacturers as they test chemicals for safety. For example, current animal safety tests do not take into account changes in hormone levels in the animal’s mammary glands in response to exposure to chemicals. And although high throughput tests in cells have been used to identify chemicals that activate the estrogen receptor and mimic estrogen, the tests have not been used to identify chemicals that increase estrogen or progesterone synthesis.
“This study shows that a number of chemicals currently in use have the ability to manipulate hormones that are known to negatively affect breast cancer risk,” said Dr. Sue Fenton, study co-editor and expert on mammary development at the National Institute of Environmental Health Sciences. “Of particular concern are the number of chemicals that alter progesterone, the potential culprit in hormone replacement therapy. Chemicals that increase breast progesterone levels should be minimized,” added Dr. Fenton added.
In their study, the researchers outlined a number of recommendations to improve chemical safety tests to identify potential breast cancer pathogens before they get into products, and suggest ways to reduce people’s exposure, especially during critical stages of development, like during puberty or pregnancy when the breast is going through important changes. The project is part of the Silent Spring Institute’s Safer Chemicals program, which is developing new low-cost methods of screening chemicals for their effects on the breast. The knowledge generated through these efforts will help government agencies regulate chemicals more effectively and help companies develop safer products. (ANI)
(This story was not edited by Devdiscourse staff and is automatically generated from a syndicated feed.)