Women with elevated blood concentrations of two widely used “forever chemicals” face a significantly higher risk of developing a particularly aggressive form of breast cancer, according to new research from the National Institutes of Health (NIH). The study, published in the Journal of Clinical Oncology, identified a strong connection between perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) and estrogen receptor-negative (ER-negative) breast cancer.
NIH Study Findings on PFOA and PFOS
The research analyzed data from the Sister Study, a major project conducted by the NIH’s National Institute of Environmental Health Sciences (NIEHS). Between 2003 and 2009, the study enrolled 50,884 women aged 35 to 74 from across the United States and Puerto Rico. All participants were free of breast cancer at enrollment, though each had a sister who had been diagnosed with the disease.
For this specific investigation, scientists examined blood samples from 1,609 women who later developed breast cancer and compared them with a control group of 2,269 women. The analysis measured concentrations of 17 different per- and polyfluoroalkyl substances (PFAS), which are a large family of chemicals used in numerous consumer products and known for their ability to persist in the environment and human body.
The results showed substantial differences in risk based on exposure levels. Women in the highest PFOA exposure group had a 67% higher rate of ER-negative breast cancer than those in the lowest group. The association was even stronger for PFOS, with the highest exposure group showing a 93% higher rate, nearly double that of the lowest group.
These percentages represent relative differences between groups rather than the absolute probability that an individual woman will develop the disease. The findings establish an association, not proof that the chemicals directly cause the cancer.
Understanding ER-Negative Breast Cancer
ER-negative breast cancer differs from more common forms of the disease because its tumor cells lack the receptors that allow estrogen to stimulate cancer growth. These cancers are often more aggressive and generally have poorer outcomes than tumors that respond to estrogen. Despite their severity, researchers have historically had relatively little information about what makes someone more likely to develop this specific type of cancer.
The new findings suggest that exposure to certain persistent environmental chemicals could be one contributing factor. Because the strongest associations appeared in tumors that lack estrogen receptors, the findings suggest that PFAS could act through biological processes unrelated to hormonal signaling. Potential explanations include changes in gene activity or alterations in the immune system, though the study did not directly investigate these mechanisms.
“Our findings, which we confirmed using a meta-analysis of prior research, indicate that certain legacy PFAS, including PFOA and PFOS, are associated with a higher risk of ER-negative breast cancer, a more aggressive tumor type with few known risk factors,” explained NIH Stadtman Investigator Alexandra White, Ph.D., who led the study.
Public Health Implications and Future Research
Although PFOA and PFOS have largely been phased out and replaced with other PFAS compounds, measurable amounts of both substances are still present in most people’s bodies. Their persistence means that exposure to these older chemicals remains a potential public health concern.
Researchers emphasize that exposure is not necessarily unavoidable. “These findings matter for women’s health broadly,” said first author Che-Jung Chang, Ph.D. “Although PFAS are persistent in the environment and in our bodies, exposure to them is still potentially modifiable, meaning people can take steps to reduce their exposure, and these findings could open new avenues for prevention.”
HHS Secretary Robert F. Kennedy, Jr., commented on the findings, stating, “Women deserve clear answers about how chemicals in their environment may affect their health. This NIH study links two forever chemicals to a higher risk of ER-negative breast cancer and demands further investigation. Under President Trump’s leadership, we will pursue the evidence, confront environmental health risks, and give women the information they need to protect their health.”
The researchers say additional investigations should focus on populations with greater PFAS exposure, as well as groups that experience higher rates of ER-negative breast cancer. Scientists also need to determine whether the newer chemicals introduced as replacements for PFOA and PFOS carry similar health concerns. “More research is needed, particularly evaluating the risk of breast cancer associated with newer replacement PFAS chemicals,” White said.
Source: ScienceDaily
