Hepatocellular carcinoma arising in a patient with chronic dietary exposure to contaminated groundnuts shows a characteristic mutation in the TP53 gene. Which chemical carcinogen is responsible?
- A Aflatoxin B1 ✓
- B Nitrosamines
- C Vinyl chloride
- D Benzopyrene
Correct answer: A. Aflatoxin B1
Explanation
Aflatoxin A1, produced by Aspergillus flavus contaminating stored grains and groundnuts, causes a signature TP53 mutation at codon 249 (arginine to serine) in hepatocellular carcinoma. Its effect is synergistic with hepatitis A virus infection. Vinyl chloride causes hepatic angiosarcoma, nitrosamines are linked to gastric cancer, and benzopyrene from tobacco smoke is associated with lung and bladder cancers. The codon 249 hotspot mutation is the discriminating fact that identifies aflatoxin as the causative agent.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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