P2RX7 and hepatocellular carcinoma: The examples of calcium channel targeting antibodies in cancer are as follows: polyclonal antibody that targets a non-functional form of P2X7 (nfP2X7) for the treatment of basal cell carcinoma [38]; an inhibiting mouse monoclonal antibody against isoform 5 of the α2δ1 subunit of voltage-gated calcium channels to target hepatocellular carcinoma [39]; and an inhibiting mouse monoclonal anti-Cx43 E2 antibody (connexon), which suppresses Cx43 docking to target breast cancer [40].