A 45-year-old premenopausal woman with BRCA1 mutation has a prophylactic bilateral mastectomy. Histology reveals a 6 mm grade 1 invasive lobular carcinoma in the right breast. The BRCA1 mutation most strongly predisposes to which breast cancer subtype?
- A Luminal A (ER+/PR+/HER2−, low Ki-67)
- B Triple-negative/basal-like (ER−/PR−/HER2−) ✓
- C HER2-enriched (ER−/PR−/HER2+)
- D Invasive lobular carcinoma (ER+/PR+)
Correct answer: B. Triple-negative/basal-like (ER−/PR−/HER2−)
Explanation
BRCA1 germline mutations are most strongly associated with triple-negative, basal-like breast carcinoma, which tends to be high-grade and occurs at a younger age. BRCA2 mutations are more often associated with luminal subtypes (ER+). Invasive lobular carcinoma is typically ER+ and is not specifically linked to BRCA1. The incidental finding in this question (lobular carcinoma) is a distractor.
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.