In other recent studies, Kathie Walters and Sharon Lederer have examined the gene expression profiles that differentiate alcohol-and HCV-induced liver cirrhosis [13] and the gene expression patterns associated with HCV-induced pathogenesis in individuals co-infected with HIV-1 [14] . We found that global gene expression patterns vary significantly depending upon the etiology of liver disease and that stages of liver cirrhosis can be differentiated based on gene expression patterns in ethanol-induced, but not HCV-induced, disease. Many of the gene expression changes specifically observed in HCV-infected cirrhotic livers are associated with activation of the innate immune response. In contrast, we found that intrahepatic global gene expression profiles do not differ between HCV-and HCV/HIV-1 co-infected individuals. However, a specific gene expression pattern that may be associated with HCV-induced pathogenesis was identified. This pattern has similarities to the gene expression profiles in transplant patients who progress to fibrosis within one year of transplantation, suggesting it may also be relevant to predicting disease progression.