The link appeared only in estrogen receptor-negative tumors, a type Black women develop at higher rates, and researchers say future studies should focus on the women most affected.
By EEW Magazine Online Editors
A new NIH study links two common PFAS chemicals to higher rates of estrogen receptor-negative breast cancer, a type Black women develop more often. (Getty Images)
The nonstick skillet on the stove, the takeout wrapper on the counter, the water-repellent jacket by the door. For decades, everyday products like these were made with a family of chemicals that barely break down, and two of the most common ones have now been linked to a harder-to-treat form of breast cancer.
In a study published Nov. 5 in the Journal of Clinical Oncology, National Institutes of Health researchers found that women with higher blood levels of PFOA and PFOS were more likely to develop estrogen receptor-negative breast cancer.
The chemicals belong to a large group called per- and polyfluoroalkyl substances, or PFAS. They earned the nickname "forever chemicals" because they resist breaking down in the environment and can remain in the human body for years.
PFOA and PFOS have largely been phased out and replaced with newer PFAS compounds. Most people still have measurable levels of both in their blood.
The findings land close to home for Black women. According to the American Association for Cancer Research, Black women experience higher rates of ER-negative and triple-negative breast cancers, aggressive forms whose causes scientists understand far less.
A mammogram appears on a monitor at Derby City Hospital in England. Regular screening remains one of the most important steps a woman can take for her breast health. (Rui Vieira/PA Images via Getty Images)
The researchers drew on the Sister Study, a long-running NIH project that enrolled 50,884 women ages 35 to 74 from 2003 to 2009. None had breast cancer when they joined. Each had a full or half-sister who had been diagnosed with the disease.
From that group, the team analyzed 1,609 women who later developed breast cancer and a comparison sample of 2,269 women. They measured 17 types of PFAS in blood collected years before any diagnosis.
Women with the highest PFOA levels had a 67% higher rate of ER-negative breast cancer than women with the lowest levels. For PFOS, the rate was 93% higher, nearly double.
Both figures compare groups of women with one another. Neither describes an individual woman's chance of getting breast cancer.
The researchers found no clear link between either chemical and breast cancer overall. The higher rates showed up only in ER-negative tumors, which lack the receptors that let estrogen fuel cancer growth. These cancers tend to be more aggressive, have worse outcomes and do not respond to the hormone-blocking drugs used for many other breast cancers.
"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," said Alexandra White, an NIH Stadtman investigator who led the study.
That meta-analysis pooled seven earlier studies that also measured PFAS in blood before diagnosis. It supported the PFOA finding with statistical confidence. Results for PFOS pointed in the same direction but were less conclusive.
The study was observational, so it shows an association and cannot prove the chemicals cause cancer. Every participant also had a sister with breast cancer, so the group does not mirror the general population. The authors suggest PFAS could affect cancer risk through changes in gene activity or the immune system, though the study did not test those ideas.
The gap for Black women is widest with triple-negative breast cancer. Black women have about twice the incidence rate of women in every other racial and ethnic group, according to the AACR's 2026 Cancer Disparities Progress Report. That subtype lacks estrogen receptors, progesterone receptors and a protein called HER2, which limits treatment options. Every triple-negative tumor is ER-negative, though the ER-negative category is broader.
The study’s authors say future research should focus on women with higher PFAS exposure and on groups more affected by ER-negative breast cancer. (Nitat Termmee/Getty Images)
The same report found breast cancer death rates 35% higher among Black women than white women, even though Black women were diagnosed at a 6% lower rate. The AACR attributes such gaps to a mix of structural, social, environmental and biological factors.
The NIH study did not examine whether PFAS help explain those disparities, and the agency's announcement does not break down the findings by race. The authors say future research should focus on people with higher PFAS exposure and on groups more affected by ER-negative breast cancer.
PFAS exposure is widespread, and some of it is within a woman's control. The Environmental Protection Agency advises residents to contact their local water utility or state health department to learn whether PFAS have been found in their drinking water and what officials recommend.
For households that want a filter, the EPA says to choose one certified to reduce PFAS under NSF/ANSI 53 or NSF/ANSI 58, the standard for reverse osmosis systems. The certification appears on the packaging or the manufacturer's website. Cartridges need replacing on schedule to keep working.
Women can also look for cookware, furniture and clothing made without added PFAS when replacing items sold as nonstick, stain-resistant or water-repellent.
A PFAS blood test will not answer the larger question. The CDC's Agency for Toxic Substances and Disease Registry says such tests show how much of certain chemicals are in the blood but cannot pinpoint a health problem or predict future illness. Knowing family history, keeping up with screening and talking with a doctor about personal risk remain a woman's strongest protections.
ER-negative breast cancer has few known risk factors, which gives the new research its weight. First author Che-Jung Chang, a former NIH research fellow now with the research firm DLH, told Fox News that although PFAS are "persistent" in the environment and the body, exposure is "potentially modifiable."
If future studies confirm the link, women would have something rare in the fight against aggressive breast cancer: a risk they can work to reduce.