A key role in the cytotoxicity of NK cells is played by receptors activating mainly NKG2-D type II integral membrane protein (NKG2D) and their NKG2DL ligands, including MICA, MICB, ULBP1, and ULBP2, which are expressed on CML blasts. Here, KLRK1 is linked to chronic myelogenous leukemia, BCR-ABL1 positive.