Association Between HBx Variations and Development of Severe Liver Disease Among Indonesian Patients.

TLDR: The development of multi-site mutations in the X gene may represent a strategy by which HBV can escape immune surveillance and thus contribute to hepatocarcinogenesis, even though the biological roles of some variants remain unclear.

Abstract: Multi-site mutations in the hepatitis B virus (HBV) X gene are often found in patients with advanced liver diseases such as liver cirrhosis and hepatocellular carcinoma. It has been reported that modifications in the X protein play crucial roles in the development of HBV-related severe liver disease. However, the prevalence of genetic variations in Indonesian strains has not been systematically assessed. In this study, we sought to investigate the profile of nonsynonymous mutations in the X gene. Overall, 114 Indonesian HBV strains, including 12 in-house samples, were retrieved from GenBank. The mutation frequency in the X gene was compared among strains obtained from patients with chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma. The mutation frequencies of the domain and basal core promoter regions were significantly greater in advanced liver diseases compared with chronic hepatitis. In addition, the double mutation K130M/V131I and the triple mutation N88V/K130M/V131I were associated with a 2.5 times higher risk of advanced liver disease. However, the roles of two novel X gene mutations (A12S/T and L16F/P) on hepatocarcinogenesis are unclear relative to wild-type X gene. In conclusion, the development of multi-site mutations in the X gene may represent a strategy by which HBV can escape immune surveillance and thus contribute to hepatocarcinogenesis, even though the biological roles of some variants remain unclear.