NIH Cohort Study Associates PFOA and PFOS Exposure With Elevated ER-Negative Breast Cancer Incidence

An NIH analysis of the Sister Study found higher prediagnostic PFOA and PFOS levels associated specifically with ER-negative breast cancer. The observational findings point to modifiable environmental risk factors and non-hormonal mechanisms but require replication in higher-exposure populations. Evidence quality supports association but not causation pending further interventional or mechanistic data.