Epidemiologic studies of hepatocellular carcinoma in regions with contaminated grain stores show a characteristic mutation signature in the tumor suppressor gene TP53. Which chemical carcinogen accounts for this pattern?

• A Aflatoxin B1 ✓
• B Nitrosamines from tobacco smoke
• C Vinyl chloride
• D Benzidine dye

Explanation

Aflatoxin B1, produced by Aspergillus flavus contaminating stored grains and peanuts, forms adducts that cause a characteristic G to T transversion at codon 249 of TP53 in hepatocellular carcinoma. This mutation acts synergistically with chronic hepatitis B infection. Vinyl chloride causes hepatic angiosarcoma, benzidine causes bladder urothelial carcinoma, and tobacco nitrosamines produce a broader spectrum of mutations without the codon 249 signature.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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