HLA-E and colorectal carcinoma: In parallel, some in vitro data based on CRC cell line demonstrated that the non-classical major histocompability complex (MHC) Class I, human leucocyte antigen E (HLA-E) expressed by tumor cells and stabilized by β2 microglobulin (β2m) co-expression, inhibits the cetuximab-mediated cellular cytotoxicity induced by natural killer (NK) cells.