KLRD1 and neoplasm: Various solid and hematopoietic cancers demonstrated a downregulation of the activating receptors NKp30, NKG2D, NKp46 and CD16 and an increase of soluble NKG2D ligands sMICA/B shed from the tumor cell surface, but high expression levels of the inhibitory receptor CD94/NKG2A, resulting in impaired NK cell cytotoxicity (78).