Study finds common chemicals may alter normal breast development

A recent study from Tufts University School of Medicine and Boston University reveals that exposure to common chemicals, particularly a mixture of three bisphenols, may alter the normal development of human breast tissue. The findings, published in the Proceedings of the National Academy of Sciences, suggest that these molecular changes could potentially increase susceptibility to breast cancer later in life.

The researchers used three-dimensional organoids, grown from breast tissue donated by healthy young women, to mimic human breast tissue development. The organoids were exposed to individual chemicals and mixtures, including endocrine-disrupting substances, metabolism-affecting chemicals, and carcinogens. The most significant discovery involved the combination of three bisphenols—BPA, BPS, and BPF—individually causing few changes but together disrupting normal breast development in most donors.

The molecular changes associated with the bisphenol mixture closely matched patterns found in invasive lobular breast cancer, the type that may not cause detectable lumps and can be difficult to identify with mammograms. However, the study does not establish a direct link between the chemicals and cancer or determine the risk level in humans.

Instead, the research highlights a new method for investigating how environmental exposures may subtly alter normal tissue development, potentially leaving behind molecular markers that could aid in identifying individuals at higher risk and informing earlier or more targeted screening. Further studies with larger and more diverse donor groups and a wider range of chemicals are needed to validate the findings and assess their applicability to human breast cancer risk.