Neoplasia USMLE Step 1 Practice Question
A 62-year-old man with a 40 pack-year smoking history presents with a 3-week history of hemoptysis and progressive dyspnea. Physical examination reveals decreased breath sounds over the right upper lung field. Vital signs: BP 138/82 mmHg, HR 102/min, RR 20/min, SpO2 92% on room air. Chest X-ray shows a 4-cm right upper lobe mass with ipsilateral hilar lymphadenopathy. CT of the chest and abdomen demonstrates mediastinal involvement and adrenal metastases. Bronchoscopic biopsy confirms small cell lung cancer (SCLC) with neuroendocrine features. Serum neuron-specific enolase is elevated at 28 ng/mL (normal <12.5 ng/mL). Which of the following molecular and cellular features best accounts for this tumor's rapid progression and early distant metastatic disease?
Answer choices
- AInactivation of p53 and Rb tumor suppressors with high proliferation rate and early hematogenous disseminationCorrect answer
- BOverexpression of HER2 receptor with amplification of chromosome 17
- CChronic Epstein-Barr virus integration into the tumor genome
- DPhiladelphia chromosome with BCR-ABL fusion resulting in constitutive tyrosine kinase activity
- ELoss of adenomatous polyposis coli (APC) gene leading to Wnt signaling activation
- FEGFR mutation with increased sensitivity to epidermal growth factor signaling
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