CD244 and neoplasm: Some of the notable NK cell receptors that are associated with tumor surveillance and could provide therapeutic targets for leukemia treatment are natural killer group 2D (NKG2D), DNAM-1, PD-1, 2B4 (CD244, SLAMF4), CS1(CD319, SLAMF7), LLT1 (CLEC2D, OCIL), aKIRs and iKIRs, and natural cytotoxicity receptors (NCRs) such as NKp44, NKp30, and NKp46 (Figure 1).