BRCA1

BRCA1 (breast cancer type 1 susceptibility protein) is a human tumor suppressor gene that encodes a protein essential for the maintenance of genomic stability. BRCA1 functions primarily in the repair of DNA double-strand breaks through homologous recombination repair (HRR), and it also participates in DNA damage signaling, cell-cycle checkpoint control, chromatin regulation, and transcriptional responses to genotoxic stress. Loss of BRCA1 function impairs accurate DNA repair and promotes genomic instability, which underlies its central role in hereditary breast and ovarian cancer predisposition.

Clinically, pathogenic BRCA1 variants are associated with increased lifetime risk of breast and ovarian cancer and are also relevant in other tumor types where homologous recombination deficiency influences treatment response. BRCA1 status is therefore used as a biomarker for DNA repair defects and for sensitivity to therapies such as PARP inhibitors, including olaparib and other poly(adenosine diphosphate ribose) polymerase inhibitors. In recent research, BRCA1 has also been examined in relation to tumor microenvironment features, metabolic phenotypes, and therapeutic vulnerabilities in cancers such as lung adenocarcinoma, pancreatic cancer, colorectal cancer, and breast cancer.