Hepatitis B Virus PreS Variant and Hepatocellular Carcinoma

Hepatocellular carcinoma (hcc) is one of the most common cancers in the world. hcc is associated with multiple riskfactors. although the association between chronic hepatitis b virus (hbv) infection and hcc is well established, theunderlying mechanism of hbv-related hepatocarcinogenesis still remains elusive. viral proteins such as x protein andthe truncated middle s protein have been implicated to be tranactivators. recently, studies are focused on mutationswithin the hbv genome that may be associated with hcc. deletions in the 3' end of pres1 and 5' terminal of pres2 mayemerge during the course of chronic hbv infection which may potentially lead to impairment in immune clearance ofthese variants. the pres mutant proteins are localized in the endoplasmic reticulum (er) and have been implicated inthe induction of er stress responses. the er stress response induces a series of signal transduction pathways andoxidative dna damage. furthermore, pres2 mutant protein can upregulate cyclin a expression and induce nodularproliferation of hepatocytes. the findings in this review are important to study the correlation between hcc and presdeletion mutants.