BRCA1 Gene

The BRCA1 gene (BRCA=acronym for Breast Cancer 1) is located on chromosome 17q21.31 and encodes a 190 kD nuclear phosphoprotein that plays a role in maintaining genome stability and also acts as a tumor suppressor. The BRCA1 gene contains 22 exons spanning approximately 110 kb of DNA.

The encoded protein, together with other tumor suppressors, DNA damage sensors, and signal transducers, forms a large protein complex with multiple subunits known as the BRCA1-associated genome surveillance complex (BASC). This gene product associates with RNA polymerase II and also interacts with histone deacetylase complexes through the C-terminal domain. The BRCA1 protein plays a role in transcription, DNA repair of double-strand breaks, and recombination.

Mutations in this gene are responsible for approximately 40% of hereditary breast cancers and more than 80% of hereditary breast and ovarian cancers.

Furthermore, variants that have been shown to impair the function of the protein increase the risk of prostate and pancreatic cancers. These findings have led to the increasing popularity of genetic testing for risk assessment in healthy individuals. Recent ovarian cancer studies have also shown that BRCA mutation status can predict response to treatment.

PARP inhibitors for BRCA-positive ovarian cancers led. These studies have led the Society of Gynecologic Oncology to recommend BRCA germline testing in all patients diagnosed with ovarian cancer.