Aflatoxin and p53 abnormality in duck hepatocellular carcinoma.

Recent studies have revealed that a point mutation at codon 249 in the p53 gene predominates in hepatocellular carcinoma (HCC) cases from Southern Africa and China, where infection with hepatitis B virus (HBV) and contamination of aflatoxin B1 in food are risk factors for HCC. This unique mutation from G to T at the third base in codon 249 observed in human HCC cases is suggested to be linked to aflatoxin exposure. Six ducks with HCC, five of which were fed a diet containing aflatoxin B1 for 1-2 years, were analysed for the presence of point mutations at this codon of the p53 gene by polymerase chain reaction and direct nucleotide sequencing. None of the six ducks with HCC showed the change at this codon regardless of duck hepatitis B virus infection. This suggests that aflatoxin B1 itself might not be involved in the unique mutation at codon 249 in hepatocarcinogenesis, or that other factors coincident with aflatoxin may be responsible for this unique mutation.