CD226 and acute myeloid leukemia: Studies evaluating the expression of these molecular receptors on NK cells showed the underexpression of activating receptors such as NKG2D, NCRs and DNAX accessory molecule-1 (DNAM-1) as well as overexpression of inhibitory receptors such as KIR2DL2/L3 and NKG2A in AML patients as compared with healthy controls [48–52].