Schroeder J, et al., 2024

Breast cancer is one of the most common cancers in the world, and some aggressive types—like triple-negative breast cancer (TNBC)—affect Black women more often than other groups. Recent research suggests that TNBC may develop when certain normal breast cells change, gain new characteristics that make the cancer more aggressive. This process, called phenotypic plasticity, allows cells to shift their identity, which may help cancer grow and spread. Scientists think that exposure to certain chemicals in the environment could play a role in triggering these changes. However, little is known about how these chemicals affect cause these changes.

This study uses breast cells established from women who donated breast tissue to the Komen Tissue Bank. It explores whether eight common environmental chemicals can cause cells to gain new characteristics, which could help explain why some people are at higher risk for aggressive breast cancer.

1. More Hybrid Cells: Some chemicals, like BPA, BPS, and DDE, increased the number of hybrid cells. Hybrid cells are linked to more aggressive tumor behavior, suggesting these chemicals might trigger cancer-like changes in normal breast cells.
2. Racial Differences in Cell Changes: Breast cells from Black women were more likely to change types after exposure to these chemicals compared to cells from White women. This could help explain why Black women are more likely to develop aggressive cancers like TNBC.
3. Different Effects from Different Chemicals: Each chemical caused specific changes. For example, BPA and BPS increased the number of hybrid cells and boosted cell growth, while arsenic and lead reduced cell numbers, showing their potential toxic effects.

This study provides evidence that exposure to common environmental chemicals may increase the likelihood of breast cells undergoing changes linked to aggressive cancer types like triple-negative breast cancer (TNBC). Because Black women are diagnosed with TNBC at higher rates and tend to face worse outcomes, these findings suggest that environmental exposures could be one factor contributing to this racial disparity.

Certain chemicals tested in this study, like BPA and DDE, are widely present in plastics, food packaging, and industrial pollution, and Black women are more likely to be exposed to some of these chemicals due to systemic factors such as differences in housing, work exposures, and personal care product use. If these chemicals promote cell changes that make TNBC more likely, reducing exposure in at-risk communities could be an important step toward addressing disparities in breast cancer outcomes. Further research is needed to confirm these effects in real-world conditions and to explore policies that could help limit exposure to harmful environmental chemicals.