Twenty-three proteins were validated, including known biomarkers (e.g., VWF, PPBP) and newly identified biomarkers of HCC (e.g., ANPEP, PIGR, AFM) and LC (e.g., CPN2) (supplemental Fig. S16; Table 3 and supplemental Table S19). Here, CPN2 is linked to hepatocellular carcinoma.