Galectin-3-binding protein (LG3BP) and polymeric immune receptor (PIGR) in serum exosomes show better diagnostic value for HCC (area under the curve (AUC): LG3BP = 0.904 and PIGR = 0.837, respectively) compared with that of alpha fetoprotein (AFP) (AUC: 0.802), which is most commonly used as a noninvasive serum indicator of HCC. Here, PIGR is linked to hepatocellular carcinoma.