Our results confirm that a downregulation in the expression of activating NK cell receptors may contribute with an inefficient killing of leukemic cells, a phenomenon also observed in other hematological malignancies including acute myeloid leukemia, where a diminished expression of NCRs, DNAM and NKG2D has been suggested to explain the resistance of myeloid leukemias to NK-mediated lysis (70). Here, KLRK1 is linked to myeloid leukemia.