KROK 1 2014 – Question 195 · KROK (Medicine) · Biological Chemistry
In cancer patients who have been continuously receiving methotrexate, the target cells of tumor with time become insensitive to this drug. In this case, gene amplification of the following enzyme is observed:
- A. Thiaminase
- B. Thioredoxin reductase
- C. Dihydrofolate reductase
- D. Deaminase
- E. -
Hint
Think about how tumour cells overcome a competitive enzyme inhibitor by changing the number of copies of the gene that encodes the drug's target.
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