p53 gene in hepatocellular carcinomas from Australia.

The p53 protein is now well established as a crucial player in regulation of cell growth. Mutations arising in the coding sequences of its gene have been demonstrated in a wide variety of human tumors, including hepatocellular carcinoma (HCC). Our previous studies have shown that codon 249 mutations, the most common mutation of the p53 gene in HCCs, did not occur in our group of patients. To examine the prevalence of p53 mutations in other areas of the p53 gene, PCR and direct sequencing were carried out on these samples covering the four highly conserved regions of the gene between exons 5 and 8. Liver samples were obtained from both HBV+ and HBV- patients in a variety of ethnic groups. Primers to the flanking regions of exon 5, 6, 7, and 8 were used in PCR to amplify these exons. Following purification, the products were sequenced in both directions by cycle sequencing. In 15 HCCs examined, no mutations in these exons of the p53 gene were found. This suggests a less important role for p53 in development of HCC in this group of patients than in patients from other areas of the world.