KLRK1 and neoplasm: As an example, TGF-β-mediated downregulation of CX3CR1 can limit NK cell migration towards the tumor site (25); similarly, the downregulation of activating receptors including NKG2D and NKp30 as well as the adaptor proteins DAP10 and DAP12 triggered by TGF-β diminishes human NK cell cytotoxicity in vitro (26–28, 111).