Epoxidation of aflatoxin to 8, 9-epoxide by CP450 enzyme plays pivotal role in the pathway of the hepatocellular carcinoma; bind the guanine bases particularly on the third base of codon 249 of the p53 gene to form aflatoxin-N7-guanine (AFB1-N7-Gua). The gene discussed is TP53; the disease is hepatocellular carcinoma.