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. The gene discussed is KLRD1; the disease is neoplasm.