Abstract: Objective To investigate the relevance of the basic core promoter(BCP) mutants of integrated hepatitis B virus(HBV) in liver tissues from patients with hepatocellular carcinoma(HCC).
Methods Alu repeat sequence polymerase chain reaction(Alu-PCR) and ligation-mediated(LM)PCR were used to identify the HBV integration in 40 pairs of HBV-related HCC tissues and adjacent non-tumorous liver tissues. The PCR products were purified and subjected to direct sequencing by ABI 3700 Auto sequencer. NCBI BLAST and Bio Edit software were used for analysis of HBV sequence.
Results In 40 HBsAg positive HCC samples, 26(65.0%) showed HBV integration in host genome, with a total of 37 different HBV integrated fragments. In adjacent liver tissues, 27(67.5%) showed HBV integration, and with a total of 68 different HBV integrated fragments in host genome. The HCC showed an average of 1.42 HBV integration events per tissue, which was significantly lower than that in adjacent liver tissues(2.52). Further sequence analysis revealed a tendency of increased A1762T/G1764A mutation frequency from adjacent liver tissues to HCC tissues, although the difference was not statistically significant.
Conclusion The high frequencies of HBV integration in both tumor and adjacent non-tumor tissues demonstrated again that hepatitis B virus integration occurred in early stage during HCC development. In addition, integrated hepatitis B virus DNA containing core promoter mutations at nucleotides 1762 and 1764 was also found both in hepatocellular carcinoma and adjacent tissues, with increasing frequency from adjacent tissues to HCC, suggesting the possibility that insertional mutagenesis resulting from hepatitis B virus integration could play a role in hepatocarcinogenesis in some patients.

Key words: hepatocellular carcinoma, hepatitis B virus, integration, mutation