We hypothesized that pretreatment nonresponder and responder liver tissue would show consistent differences in gene expression levels and that these differences could be used to predict treatment outcomes and this can obviate the need of the present therapeutic trial.We are interested in conducting a retrospective study using the data of patients suffering from chronic HCV infection who were treated in our department with a combination of PEGINTERFERON and RIBAVIRIN. All these patients underwent liver biopsy prior the treatment. Based on the clinical data available it is possible to determine the responders and nonresponders to this therapy.RNA will be extracted from the liver tissue and the expression of 5 genes(IFI15,IFI616,IFI1,OAS3,OAS2 )will be checked .The prediction power of the combination of these genes in differentiating responders from nonresponders will be determined.