Various state and international organizations have among their objectives the health surveillance of consumer products and substances to which humans may be exposed. The International Cancer Research Center (IARC), for example, is an intergovernmental body that is part of the United Nations World Health Organization and, as its name suggests, focuses on cancer studies. , including a system of listing products for their potential relationship with cancer.
Despite the existence of this type of organisms and the equally extensive regulations on this matter, there are still thousands of synthetic chemicals potentially harmful to health on the market.
A study led by the Silent Spring Institute (United States) has thoroughly reviewed this problem and focused on the potential risks for breast cancer. After analyzing thousands of studies on compounds and effects, those responsible for this research have found a quick way to predict whether a chemical substance is likely to cause breast cancer, according to an article published (January 10) in the journal Environmental. Health Perspectives.
“This new study provides a roadmap for regulators and manufacturers to quickly detect chemicals that could contribute to breast cancer in order to prevent their use in consumer products and find safer alternatives,” says lead author, Dr. Jennifer Kay, research scientist at Silent Spring Institute.
Breast cancer is one of the diseases with the highest incidence in the world and recent data shows that rates are increasing in young women, a trend that cannot be explained by genetics, explains Dr. Kay. “We need new tools to identify environmental exposures that could be contributing to this trend, so that we can develop prevention strategies and reduce the burden of disease,” details the lead author of the new study.
The Silent Spring Institute team (which takes its name from the well-known documentary book by Rachel Carson, translated as Silent Spring) reviewed multiple international and United States government databases with the aim of identifying chemicals that cause mammary tumors in animals ( models that can serve as a basis for possible similar effects in humans).
The researchers also analyzed data from the United States Environmental Protection Agency’s (EPA) ToxCast program to identify chemicals that disrupt human hormones or endocrine disruptors, in processes that could promote breast cancer. The team specifically looked for chemicals that activate the estrogen receptor (a receptor present on breast cells), as well as chemicals that cause the cells to produce more estrogen or progesterone, an established risk factor for breast cancer.
The now published report identifies a total of 921 chemicals that could promote the development of breast cancer. The authors indicate that 90% of these chemical substances are present in products or environments to which people are commonly exposed (consumption, food, beverages, pesticides, medications, workplaces…)
A breakdown of the list revealed 278 chemicals shown to cause mammary tumors in animals. More than half of the chemicals cause cells to produce more estrogen or progesterone, and about a third activate the estrogen receptor. “Breast cancer is a hormonal disease, so the fact that so many chemicals can alter estrogen and progesterone is worrying,” says Dr. Kay in a note released by her institute.
Since DNA damage can also trigger cancer, the researchers searched additional databases and found that 420 of the chemicals on their list damage DNA and disrupt hormones, which could make them more dangerous. What’s more, the team’s analysis found that chemicals that cause mammary tumors in animals are more likely to have these DNA-damaging and hormone-disrupting characteristics than those that do not.
“Historically, chemicals that cause breast tumors in animals were considered the best predictor of whether they could cause breast cancer in humans,” says co-author Ruthann Rudel, research director at the Silent Spring Institute.
Over the past decade, there has been increasing evidence that environmental chemicals are important factors contributing to the development of cancer, recalls the Silent Spring Institute. Several studies in people have found links between breast cancer and pesticides, hair dyes, and air pollution. Other studies suggest that exposure to hormone-disrupting chemicals early in life, in utero or during puberty, may alter breast development in ways that could increase the risk of cancer later in life.
However, to see those associations, scientists have to wait until hundreds or thousands of children and women have been exposed to a chemical and see, often many years later, who develops breast cancer. “It is neither feasible nor ethical to wait that long,” says Dr. Rudel. “And it’s another reason why we need better tools to predict which chemicals are likely to cause breast cancer so we can avoid those exposures.”
The study’s authors hope that their new comprehensive list of chemicals relevant to breast cancer, which includes hundreds of endocrine disruptors, will serve as a basis for agencies like the EPA or IARC to better protect the public from harmful exposures.