CIN (cervical intraepithelial neoplasia) grade 3 is defined as full-thickness atypia of squamous epithelium. Which HPV proteins are responsible for inactivating p53 and Rb in high-grade CIN?
- A E7 inactivates p53; E6 inactivates Rb
- B E6 inactivates both p53 and Rb
- C E6 inactivates p53; E7 inactivates Rb ✓
- D L1 and L2 capsid proteins degrade p53 and Rb
Correct answer: C. E6 inactivates p53; E7 inactivates Rb
Explanation
High-risk HPV (types 16, 18) oncoproteins E6 and E7 target the two major tumor suppressors: HPV E6 binds p53 and promotes its ubiquitin-mediated degradation; HPV E7 binds and inactivates Rb, releasing E2F transcription factors to drive cell cycle progression. Together, loss of these checkpoints enables unchecked proliferation and genomic instability leading to carcinoma.
Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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