Hepatitis C virus genotypes: clinical relevance and therapeutic implications

The incidence of hepatitis C virus (HCV) -related hepatocellular carcinoma (HCC) has been increasing in several countries including Taiwan. There are six main genotypes, each of which contains closely related subtypes. Molecular epidemiological studies have shown marked differences in the genotype distribution by geographical region and between patient groups. HCV genotype 1 may play a role in the development of HCC, although some studies have argued against this. A sustained virological response secondary to interferon monotherapy or interferon/ribavirin combination therapy may reduce the risk of HCC and improve survival in chronic hepatitis C patients. The HCV genotypes are associated with therapeutic response. Rapid virological response is also a predictor of therapeutic response. Although viral characteristics have consistently been shown to be important predictors of treatment response, identification of additional host immune and genetic factors involved in determining the outcome of antiviral therapy is necessary. Newly developed bio-techniques (microarray, proteomes, bioinformatics), drugs, and treatment strategies may elucidate the pathogenesis and improve the therapeutic response in HCV infection.