The association of the antibodies to PD-1 prevents the binding of PD-1 with its ligands, PD ligand 1 (PD-L1), and 2 (PD-L2), present in tumor cells and other hepatic cells and leucocytes, and hence allows a strong T-cell response toward HCC cells [68]. This evidence concerns the gene PDCD1 and hepatocellular carcinoma.