ThechronicinfectionofhepatitisBvirus(HBV)iscloselyrelatedtotheoccurrenceanddevelopmentofhepatocellularcarcinoma(HCC).AccumulatedevidencehasshownthatHBVXprotein(HBxprotein)isamultifunctionalregulatorwithacrucialroleinhepatocarcinogenesis.However,informationonthemechanismbywhichHBVinducesHCCislacking.ThisreviewfocusesonthepathologicalfunctionsofHBxinHBV-inducedhepatocarcinogenesis.Asatransactivator,HBxcanmodulatenuclearfactorkappa-light-chain-enhancerofactivatedBcells(NF-κB)andtranscriptionfactorAP-2.Moreover,HBxcanaffectregulatorynon-codingRNAs(ncRNAs)includingmicroRNAsandlongncRNAs(lncRNAs),suchasmiRNA-205andhighlyupregulatedinlivercancer(HULC),respectively.HBxisalsoinvolvedinepigeneticmodification,includingmethylationandacetylation.HBxinteractswithvarioussignal-transductionpathways,suchasproteinkinaseB/Akt,Wnt/β-catenin,signaltransducerandactivatoroftranscription,andNF-κBpathways.Moreover,HBxaffectscellularfatebyshiftingthebalancetowardcellsurvival.HBxmayleadtothelossofapoptoticfunctionsordirectlycontributestooncogenesisbyachievingtransformingfunctions,whichinducehepatocarcinogenesis.Additionally,HBxcanmodulateapoptosisandimmuneresponsebydirectorindirectinteractionwithhostfactors.WeconcludethatHBxhastensthedevelopmentofhepatoma.
