Bisphenol Mixes Disrupt Breast Development in Lab Models

Researchers at Tufts University School of Medicine and Boston University published a pre‑clinical study that examined how exposure to common chemicals may alter normal breast development. The team, led by Charlotte Kuperwasser, used human breast organoids to model tissue changes that could influence future breast disease risk. Their findings appear in the Proceedings of the National Academy of Sciences and suggest that developmental exposure to endocrine‑disrupting chemicals may leave lasting molecular fingerprints in breast tissue.

Modeling chemical exposure in human tissue

To capture the complexity of human breast tissue, the scientists grew three‑dimensional organoids from tissue donated by 13 healthy young women. Over roughly three weeks the organoids were exposed to a panel of individual chemicals and mixtures that included endocrine‑disrupting compounds, metabolic modifiers, and known or suspected carcinogens. The researchers then assessed changes in gene activity and DNA methylation to detect developmental disruption.

The most striking result involved a low‑dose mixture of three bisphenols—BPA, BPS and BPF. While each chemical alone caused few changes, the combination at concentrations similar to those found in human blood and urine disrupted normal organoid development in most donors. The mixture induced transcriptional programs associated with extracellular matrix remodeling and partial epithelial–mesenchymal transition, and the pattern matched data from patients with invasive lobular carcinoma.

The study does not prove that the chemicals cause cancer, nor does it show how the observed changes influence disease. Instead, the work establishes a new method for studying how environmental exposures may alter normal tissue before cancer appears. The authors suggest that persistent molecular changes could act as a biological record of past exposure, potentially serving as a biomarker to identify individuals at higher risk and guide earlier or targeted screening.

Meadow Parrish and Meloryn Seraj, PhD students at Tufts Graduate School of Biomedical Sciences, are co‑first authors on the paper. The team plans larger, more diverse studies to determine how widespread the findings are and whether the organoid‑derived signatures persist in human tissues. Additional research will clarify whether such molecular fingerprints contribute to breast disease in people.