In BRCA1 and BRCA2 hereditary breast and ovarian cancer syndrome, both BRCA proteins participate in which DNA repair pathway?

• A Nucleotide excision repair (NER) of UV-induced pyrimidine dimers
• B Homologous recombination (HR) repair of double-strand DNA breaks ✓
• C Mismatch repair (MMR) correcting replication errors
• D Base excision repair (BER) removing oxidized bases

Explanation

BRCA1 and BRCA2 are essential components of the homologous recombination (HR) repair pathway for DNA double-strand breaks. BRCA2 loads RAD51 recombinase onto single-stranded DNA to facilitate HR; BRCA1 acts upstream in DNA damage signaling and end resection. Loss of HR forces cells to rely on error-prone non-homologous end joining (NHEJ), causing genomic instability. This also creates therapeutic vulnerability to PARP inhibitors ('synthetic lethality'). NER is defective in xeroderma pigmentosum; MMR in Lynch syndrome.

Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.