Neoplasia USMLE Step 1 Practice Question
A 35-year-old never-smoker woman presents for evaluation of an incidental 2 cm peripheral lung nodule discovered on chest CT performed for unrelated reasons. She reports no respiratory symptoms, constitutional symptoms, or occupational exposures. Vital signs are stable. Bronchoscopic biopsy with histopathology demonstrates adenocarcinoma with mucin-producing glandular structures, columnar epithelium, and absence of squamous differentiation. Molecular testing shows EGFR wild-type status. Which of the following genetic alterations is most commonly associated with this histologic subtype of lung adenocarcinoma?
Answer choices
- AEGFR exon 19 deletion
- BKRAS G12C mutationCorrect answer
- CRB1 homozygous deletion
- DTP53 missense mutation
- EBRAF V600E mutation
- FMET exon 14 skipping mutation
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.