A 48-year-old woman with invasive ductal carcinoma of the breast is found to have a BRCA1 pathogenic variant. She opts for risk-reducing contralateral prophylactic mastectomy alongside therapeutic mastectomy. Which statement about BRCA1-associated breast cancer is most accurate?
- A BRCA1-associated cancers are typically triple-negative with a basal-like phenotype ✓
- B BRCA1-associated cancers are predominantly ER-positive and HER2-positive
- C BRCA1 mutation confers mainly lobular carcinoma histology
- D BRCA1-associated cancers have a better prognosis than sporadic cancers due to intact BRCA2
Correct answer: A. BRCA1-associated cancers are typically triple-negative with a basal-like phenotype
Explanation
BRCA1-associated breast cancers characteristically demonstrate a triple-negative (ER-negative, PR-negative, HER2-negative) phenotype with basal-like gene expression profile, high grade, pushing borders, and lymphocytic infiltrate. This explains their relative resistance to hormone therapy and trastuzumab but sensitivity to DNA-damaging agents and PARP inhibitors. BRCA2 mutations more commonly produce ER-positive cancers. The prognosis is stage-dependent; triple-negative biology carries worse prognosis per stage.
Reference: Bailey & Love's Short Practice of Surgery, 27th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.