Which of the following represents an epigenetic mechanism of carcinogenesis that silences tumor suppressor genes without altering the DNA sequence?
- A Missense point mutation
- B Frameshift mutation due to microsatellite instability
- C Promoter CpG island hypermethylation ✓
- D Gene amplification
Correct answer: C. Promoter CpG island hypermethylation
Explanation
Promoter CpG island hypermethylation is a classic epigenetic mechanism that silences tumor suppressor genes (e.g., CDKN2A/p16, MLH1, BRCA1) without changing the DNA sequence. This heritable modification recruits methyl-binding proteins that condense chromatin and prevent transcription. Missense mutations, frameshift mutations, and gene amplification all alter the DNA sequence.
Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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