discovered that BM-derived myeloma cells from early-stage MM express low levels of the NK cell inhibitory ligand MHC class I and high levels of the NKG2D ligands MHC class I polypeptide-related sequence A (MICA) and MICB, whereas tumors from later-stage disease had the opposite expression pattern and were less susceptible to NK cell cytotoxicity (69). The gene discussed is MICA; the disease is plasma cell myeloma.