KLRK1 and neoplasm: Retroviral transduction of an NKG2D-DAP10-CD3ζ CAR that utilizes the extracellular domain of NKG2D for recognition of natural NKG2D ligands on the tumor cell surface, markedly increased NKG2D surface expression in NK cells, which became more cytotoxic against leukemia and solid tumor cell lines (Chang et al., 2013).