KLRK1 and neoplasm: NKG2D is an activating immune receptor expressed on NK cells that can trigger cytotoxicity and is in the CD94/NKG2 family of C-type lectin-like receptors.200,204 NKG2D binds to its ligands that occur on the surface of tumor cells, such as stem-like tumor cells, and alters these cells to be more susceptible to immune destruction.205,206 Alternatively, tumor cells can evade immune surveillance by shedding soluble NKG2D ligands.