We have confirmed the overexpression of HLA-E on the cell surface of gastric cancers and melanoma, using monospecific anti-HLA-E mAbs.(54,71) Tumor-associated HLA-E, upon binding to the inhibitory receptors (CD94/NKG2A) on NK cells or cytotoxic T cells (CD8+), inactivates the ability of such cells to kill tumor cells. This evidence concerns the gene KLRD1 and neoplasm.