In the application of our optimized RPPA system, we have detected 10 proteins, including AFP, B2M, CA15-3, CEA, GDF-15, GP73, HE4, IGFBP-2, OPN and PDGF-Rb in serum samples of 132 HCC patients and 78 healthy volunteers. Here, GDF15 is linked to hepatocellular carcinoma.