Researchers in this study wanted to understand whether air pollution—specifically fine particulate matter (PM2.5)—could affect the structure of normal breast tissue. While air pollution has been linked to breast cancer risk, the biological reasons behind this connection are not well understood. The researchers explored whether pollution might influence the makeup of breast tissue in ways that could increase cancer risk.
To investigate this, the researchers analyzed breast tissue samples from nearly 4,000 healthy women who donated tissue through the Susan G. Komen Tissue Bank. Using machine learning and digital imaging, they measured how much of the tissue was made up of epithelium (glandular cells), stroma (support tissue), and fat. They then linked these measurements to levels of air pollution based on where the participants lived.
The researchers found that higher exposure to air pollution was associated with lower amounts of stromal tissue in the breast. In some cases, depending on the type of pollution, there were also changes in the balance between epithelial and stromal tissue. These types of changes in tissue composition have previously been linked to breast cancer risk.
Overall, the study suggests that long-term exposure to air pollution may alter the normal structure of breast tissue, potentially influencing cancer development.
