HAVCR2 and hepatocellular carcinoma: The expression of T-cell immunoglobulin mucin-3 (Tim3), natural killer group 2 member A (NKG2A) and T-cell immunoglobulin and ITIM domain (TIGIT) on NK cells are increased in the tumor tissue and is correlated with impaired NK cell cytotoxicity, advanced disease stage and poor survival in CRC, GC and HCC patients [44, 45].