Metabolism USMLE Step 1 Practice Question
A 68-year-old man with a 3-month history of weight loss and anemia presents with colon adenocarcinoma. Vital signs show BP 138/82, HR 92, RR 18, Temp 37.2°C. Laboratory findings reveal hemoglobin 9.2 g/dL and CEA 18 ng/mL. Colonoscopy with biopsy confirms adenocarcinoma. Molecular analysis demonstrates maintained telomere length and escape from replicative senescence. Notably, there is no evidence of p53 mutations. Which enzyme is most likely abnormally upregulated in these malignant cells?
Answer choices
- ARNA polymerase II
- BDNA polymerase alpha
- CPrimase
- DTopoisomerase I
- ETelomeraseCorrect answer
- FTelomerase reverse transcriptase (TERT) methyltransferase
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.