BRCA1 and BRCA2 are intracellular proteins that function in the repair of double stranded DNA breaks by homologous recombination and thus function as tumor suppressors. Individuals with heterozygous mutations in either of these genes are at increased risk of breast, ovarian, and other cancers.
The BRCA1 (BReast CAncer gene 1) tumor suppressor protein has many reported functions. In addition to mediating signal transduction in DNA damage and repair responses, BRCA1 regulates transcriptional activity and assists in the preservation of chromosomal stability. BRCA1 is one of the first proteins recruited to sites of DNA double-strand breaks, and serves as part of a scaffold for assembling other DNA damage response or repair factors.