RIPK2 and hepatocellular carcinoma: To validate the different expression of the eight prognostic genes (ADORA2B, MEP1A, P2RX4, SERPINE1, ITGA5, NOD2, RIPK2 and SLC7A1) between HCC tissues and adjacent non-tumorous tissues, qRT-PCR and IHC were implemented to analyze the mRNA and protein expression respectively.