In addition to GPC3, secreted phophoprotein 1 (SPP1), vascular endothelial growth factor (VEGF), insulin-like growth factor-1 (IGF-1), and hepatocyte growth factor (HGF) have all been implicated as potential serum markers for the diagnosis of HCC [18,19,20,21,22,23]. Here, SPP1 is linked to hepatocellular carcinoma.