MADRID, 23 Jul. (EUROPA PRESS) –
A new study has just shown that several hundred common chemicals, including pesticides, ingredients in consumer products, food additives and contaminants in drinking water, could increase the risk of breast cancer by causing cells in breast tissue to produce more. amount of the hormones estrogen or progesterone.
“The connection between estrogen and progesterone and breast cancer is well established,” recalls co-author Ruthann Rudel, a toxicologist and director of research at the Silent Spring Institute, a US nonprofit NGO. be extremely cautious with chemicals in products that increase the levels of these hormones in the body. “
For example, in 2002, when the Women’s Health Initiative study found that combination hormone replacement therapy was associated with an increased risk of breast cancer, women stopped taking the drugs and incidence rates dropped.
“It’s no wonder that one of the most common therapies for treating breast cancer is a class of drugs called aromatase inhibitors that lower estrogen levels in the body, depriving breast cancer cells of the hormones that they need to grow “, adds Rudel in the article, published in the journal ‘Environmental Health Perspectives’.
To identify these chemical risk factors, Silent Spring scientist Rudel and Bethsaida Cardona examined data on more than 2,000 chemicals generated by the US Environmental Protection Agency (EPA) ToxCast program. The goal of ToxCast is to improve scientists’ ability to predict whether or not a chemical will be harmful. The program uses automated chemical screening technologies to expose living cells to chemicals and then examine the various biological changes they cause.
Rudel and Cardona identified 296 chemicals that increased estradiol (a form of estrogen) or progesterone in laboratory cells. 71 chemicals were found to increase the levels of both hormones. Among the chemicals were ingredients in personal care products such as hair dye, chemical flame retardants in building materials and furniture, and a number of pesticides.
Researchers don’t yet know how these chemicals cause cells to make more hormones. It could be that they act as aromatase activators, for example, leading to higher estrogen levels, Cardona says. “What we do know is that women are exposed to multiple chemicals from multiple sources on a daily basis, and that these exposures add up,” he says.
The researchers hope this study will be a wake-up call for regulators and manufacturers as to how they test chemicals for safety. For example, current animal safety tests do not account for changes in hormone levels in the mammary glands of animals in response to chemical exposure.
And while high-throughput tests on cells have been used to identify chemicals that activate the estrogen receptor, mimicking 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,” says Dr. Sue Fenton, associate editor of the study and an expert in the development of the mammary gland at the National Institute of Environmental Health Sciences.
It considers “of particular concern is the number of chemicals that alter progesterone, the potential bad actor in hormone replacement therapy. Chemicals that raise progesterone levels in the breast should be minimized,” he warns.
The researchers outlined a series of recommendations in their study to improve chemical safety testing to help identify potential breast carcinogens before they end up in products, and suggest finding ways to reduce people’s exposure, especially during critical periods of development, such as during puberty or pregnancy, when the breast undergoes major changes.
The project is part of the Silent Spring Institute’s Safe Chemicals Program, which is developing cost-effective new ways to test the effects of chemicals on the breasts. The knowledge generated by this effort will help government agencies regulate chemicals more effectively and companies develop safer products.
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