Pretreatment of AML-NK cells with the MAPK signaling pathway inhibitor-U0126 for 1 h had a weak to negligible cytotoxicity-reducing effect (Figure 5B) and reduced the expression of NK cells-activating receptors (NKp46 and NKG2D), with the latter decreasing more rapidly (Figures 5D,E). Here, KLRK1 is linked to acute myeloid leukemia.