Promoter CpG island hypermethylation is an important epigenetic mechanism in cancer. Which tumor suppressor gene is most commonly silenced by this mechanism in colorectal carcinoma?
- A TP53
- B RB1
- C MLH1 ✓
- D APC
Correct answer: C. MLH1
Explanation
MLH1 is the tumor suppressor gene most commonly silenced by promoter CpG island hypermethylation in colorectal carcinoma. This epigenetic change leads to microsatellite instability, seen in about 15 percent of sporadic colorectal cancer cases. TP53 is typically inactivated by point mutations, RB1 by mutations or deletions, and APC by truncating mutations. CpG island methylator phenotype is a recognized pathway in colorectal carcinogenesis.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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