Hepatocellular carcinoma and liver cirrhosis TP53 mutation analysis reflects a moderate dietary exposure to aflatoxins in Espírito Santo State, Brazil

Abstract

The close relationship between aflatoxins and 249ser TP53 gene mutation (AGG to AGT, Arg to Ser) in hepatocellular carcinoma (HCC) makes this mutation an indirect indicator of dietary contamination with this toxin. We have examined the prevalence of codon 249 TP53 mutation in 41 HCC and 74 liver cirrhosis (without HCC) cases diagnosed at the HUCAM University Hospital in Vitoria, Espírito Santo State, Brazil. DNA was extracted from paraffin sections and from plasma. The mutation was detected by DNA amplification, followed by restriction endonuclease digestion and confirmed by direct sequencing. DNA restriction showed 249ser mutation in 16 HCC and 13 liver cirrhosis, but sequencing confirmed mutations in only 6 HCC and 1 liver cirrhosis. In addition, sequencing revealed 4 patients with mutations at codon 250 (250ser and 250leu) in HCC cases. The prevalence of TP53 mutation was 10/41 (24.3%) in HCC and 1/74 (1.4%) in liver cirrhosis. No relationship between the presence of mutations and the etiology of HCC was observed. TP53 exon 7 mutations, which are related to aflatoxins exposure, were found at 14.6% (249ser), 7.3% (250leu) and 2.4% (250ser) in 41 cases of HCC and 1.4% in 74 liver cirrhosis (without HCC) cases, suggesting a moderate dietary exposure to aflatoxins in the Espírito Santo State, Brazil.