The genetics of breast cancer are complex and heterogeneous. To date, hundreds of different mutations have been identified within genes, influencing cell cycle and proliferation activity.
BRCA1 is a human gene that belongs to a class known as tumor suppressors. It is involved in DNA damage repair and transcriptional regulation, as well as other valuable functions. Because this gene maintains genomic integrity to prevent uncontrolled proliferation, variations in the BRCA1 gene have been implicated in a number of hereditary cancers, namely breast, ovarian and prostate.
Approximately 10% of breast cancers show a strong familial tendency.
Women with germline BRCA1 mutations have an 85-90% risk of developing breast cancer.
Sporadic breast cancers also demonstrate inactivation of BRCA1 by a combination of allelic loss and promoter hypermethylation.