# Forever Chemicals Linked to Aggressive Breast Cancer Risk New NIH study finds PFOA and PFOS exposure correlates with higher ER-negative breast cancer rates. - **Source:** [ScienceDaily – Health](https://www.sciencedaily.com/news/health_medicine) - **Published:** 2026-11-12 - **Topic:** [health](https://brifing.si/c/health) - **Original article:** - **On Brifing:** https://brifing.si/s/0803af6a-3189-43c7-b014-9f468c513681 ## Chemical Exposure and Cancer A new study from the National Institutes of Health identifies a link between two common forever chemicals and an aggressive form of breast cancer. Researchers focused on perfluorooctanoic acid and perfluorooctanesulfonic acid. These substances, known as PFAS, are found in many consumer products and persist in the human body for years. ## Aggressive Tumor Characteristics The study specifically highlights estrogen receptor-negative breast cancer, a type lacking receptors that allow estrogen to stimulate growth. These tumors are generally more aggressive and have poorer clinical outcomes than hormone-responsive cancers. Scientists currently have limited information regarding the specific risk factors that contribute to the development of this disease. ## Significant Statistical Correlation Researchers analyzed blood samples from 1,609 women who developed breast cancer and 2,269 in a control group. Women with the highest PFOA levels showed a 67% higher rate of ER-negative cancer. Those with the highest PFOS concentrations faced a 93% higher rate compared to the lowest exposure group in the study. ## Study Methodology and Scope The findings utilized data from the Sister Study, which enrolled 50,884 women between 2003 and 2009. Participants were aged 35 to 74 and had sisters previously diagnosed with breast cancer. By measuring 17 different PFAS chemicals in blood collected before diagnosis, scientists could effectively compare earlier exposure levels with subsequent health outcomes. ## Biological Mechanisms Under Investigation Because the strongest associations involved tumors lacking estrogen receptors, researchers suspect PFAS may act through non-hormonal pathways. Potential explanations include alterations in immune system function or changes in gene activity. However, the current study did not directly investigate these biological mechanisms, leaving the exact process of cancer development currently uncertain. ## Persistence of Legacy Chemicals Although PFOA and PFOS have been largely phased out of production, they remain detectable in most human bodies due to their environmental persistence. This legacy exposure remains a public health concern. Researchers emphasize that while these chemicals are difficult to avoid, identifying these risks could open new avenues for future prevention. ## Future Research Requirements Scientists stress the need for additional investigations, particularly regarding newer PFAS compounds introduced as replacements. Future studies should focus on populations with higher exposure levels and those experiencing elevated rates of ER-negative cancer. Understanding whether replacement chemicals carry similar health risks is essential for developing comprehensive public health strategies for women. ## Broad Public Health Implications This research highlights the critical importance of understanding how environmental exposures contribute to aggressive disease forms. While the study establishes an association rather than direct causation, it provides a foundation for further inquiry. These findings underscore the necessity of providing women with clear information to help them protect their long-term health. ## Sources covering this story - https://www.sciencedaily.com/releases/2026/11/261112025527.htm — --- _Summary written by Brifing from the original reporting. Copyright in the original article belongs to its publisher; read the full piece at the link above._