Hepatitis C Virus Genotypes: Clinical Relevance and Therapeutic Implications

The incidence of hepatitis C virus (HCV) -related hepatocellularcarcinoma (HCC) has been increasing in several countriesincluding Taiwan. There are six main genotypes, each ofwhich contains closely related subtypes. Molecular epidemiologicalstudies have shown marked differences in the genotypedistribution by geographical region and between patientgroups. HCV genotype 1 may play a role in the developmentof HCC, although some studies have argued against this. Asustained virological response secondary to interferonmonotherapy or interferon/ribavirin combination therapy mayreduce the risk of HCC and improve survival in chronichepatitis C patients. The HCV genotypes are associated withtherapeutic response. Rapid virological response is also a predictorof therapeutic response. Although viral characteristicshave consistently been shown to be important predictors oftreatment response, identification of additional host immune and genetic factors involved indetermining the outcome of antiviral therapy is necessary. Newly developed bio-techniques(microarray, proteomes, bioinformatics), drugs, and treatment strategies may elucidate thepathogenesis and improve the therapeutic response in HCV infection.