Neoplasia USMLE Step 1 Practice Question
A 39-year-old woman with strong family history of breast and ovarian cancer carries a germline BRCA1 mutation. She presents with a left breast mass; vitals show BP 118/76, HR 82, RR 16, temp 37°C, SpO2 98%. Core biopsy reveals invasive ductal carcinoma with high Ki-67 index (42%). She denies prior chemotherapy. Her tumor cells demonstrate exceptional sensitivity to poly(ADP-ribose) polymerase inhibitors. Which normal cellular process is impaired by this BRCA1 mutation?
Answer choices
- ANonenzymatic depurination
- BBase excision repair
- CNucleotide excision repair
- DHomologous recombination repairCorrect answer
- EMismatch repair
- FNon-homologous end joining
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