A new study may explain why women with a mutation in the BRCA1 gene face up to an 85 percent lifetime risk of breast cancer; researchers from the University of Michigan Comprehensive Cancer Center found that BRCA1 plays a role in regulating breast stem cells, the small number of cells that might develop into cancers.
The study, in mice and in human breast cancer cells, found that BRCA1 is involved in the stem cells differentiating into other breast tissue cells. When BRCA1 is missing, the stem cells accumulate unregulated and develop into cancer.
“Our data suggest that an important reason women with BRCA1 mutations get breast cancer is that BRCA1 is directly involved in the regulation of normal breast stem cells. In these women, loss of BRCA1 function results in the proliferation of breast stem cells. Since we believe that breast cancer may originate in these cells, this explains why these women have such a high incidence of breast cancer,” said senior study author Max S. Wicha, M.D., Distinguished Professor of Oncology and director of the U-M Comprehensive Cancer Center.