Sequential accumulation of the mutations in core promoter of hepatitis B virus is associated with the development of hepatocellular carcinoma in Qidong, China

Background/Aims To investigate the mutations in hepatitis B virus (HBV) that might be related to hepatocellular carcinoma (HCC) in the high-risk area Qidong, China. Methods DNA sequences of HBV basal core promoter (BCP) and the overlapping X gene were determined in 58 HCC and 71 chronic hepatitis (CH) patients. In addition, a consecutive series of plasma samples from 15 HCC cases were employed to compare the CP/X sequences before and after the occurrence of HCC. Results T1762/A1764 double mutation was frequently found in Qidong patients, regardless of clinical status (65.5% in HCC and 73.2% in CH, P > 0.05). Unexpectedly, the adjacent T1766/A1768 mutation significantly increased the risk of HCC (P < 0.05). Moreover, the prevalence of triple mutations in BCP was significantly higher in patients with HCC than those with CH (P < 0.05). The longitudinal study demonstrated that the mutations in BCP were gradually accumulated during the development of HCC. Colony formation assay showed while A1764 mutation alone did not alter the colony-inhibitory activity of HBx, double or triple mutations largely abrogated this effect. Conclusions The complex mutation involving T1766/A1768 was closely related to HCC. The enhanced risk of HCC caused by BCP variants could be attributable partially to the aberrant activity of HBx.