Researchers in this study wanted to understand how genetic risk for breast cancer—specifically BRCA1 and BRCA2 mutations—affects normal breast tissue before cancer develops. People with these mutations have a much higher lifetime risk of breast cancer, but it is not fully understood what changes occur in their breast tissue before tumors form.
To investigate this, the researchers analyzed normal and benign breast tissue samples from women with and without BRCA mutations. They focused on the presence of immune cells within the breast tissue, since the immune system plays an important role in detecting and responding to abnormal cells.
The researchers found that women with BRCA mutations had higher levels of immune cells in their normal breast tissue, even when no cancer was present. These immune cells were located within the breast structures where cancer typically begins. The findings suggest that the tissue environment in BRCA carriers may already be altered, possibly due to early cellular stress or damage.
Overall, the study shows that changes in the immune environment of the breast can occur before cancer develops, particularly in individuals at high genetic risk.
