PPBP and chronic hepatitis C virus infection: In the present study, we identified SAP and PPBP in EVs as candidate biomarkers for diagnosing liver fibrosis in chronic hepatitis C. In addition, we clarified that EV SAP and PPBP levels are strongly correlated with serum SAP and PPBP levels and that serum SAP and PPBP could also be markers of liver fibrosis.