P2RX4 and hepatocellular carcinoma: P2X receptors are widely expressed in the liver, including P2X1~P2X7 subtypes, P2X1R, P2X2R, P2X3R, P2X4R, and P2X7R are expressed in hepatocytes and Non-parenchymal cells, including hepatocytes, Kupffer cells, bile duct cells, hepatic stellate cell, hepatic fibroblasts, hepatocellular adenocarcinoma, and hepatocellular carcinoma (Fausther et al., 2012).