Neoplasia USMLE Step 1 Practice Question
A 52-year-old woman presents with a palpable left breast mass discovered on self-examination. Vital signs: BP 128/82, HR 92, RR 16, Temp 37°C, SpO2 98% on room air. Mammography reveals a 2.3-cm irregular mass with microcalcifications. Biopsy confirms invasive ductal carcinoma with positive HER2/neu expression and high Ki-67 index (35%). Estrogen and progesterone receptors are negative. She denies recent weight loss or lymphadenopathy. Which molecular feature most accurately predicts aggressive behavior and treatment response?
Answer choices
- ALoss of p53 tumor suppressor with retained Rb function
- BBRCA1 mutation with lymphocytic infiltration
- CEstrogen receptor positivity with low mitotic rate
- DHER2/neu overexpression and high proliferation indexCorrect answer
- EIncreased stromal fibrosis with normal angiogenesis
- FLuminal A subtype with high hormone receptor expression
See the full explanation
Get the correct-answer rationale, why each distractor is wrong, the underlying mechanism, and high-yield associations — plus adaptive practice that targets your weak areas — with a free MedBoardPRO account.