NCR3 (NKp30) is one of the natural cytotoxicity receptors (NCRs) expressed mainly on the surface of the natural killer (NK) cells. NKp30 is a major receptor targeting virus-infected cells, malignantly transformed cells, and immature dendritic cells. NCR3 (NKp30) recognizes tumor antigens B7H6, a member of the B7 family (Kaifu et al. 2011, Brandt et al. 2009). B7H6 is not expressed normally, and is found on tumor cells, and sensitizes targets to NCR3-dependent cytotoxicity by NK cells.