Since a reduction in the expression of NKG2D ligands on the cancer cell surface, which is mediated by the cleavage activity of a disintegrin and metalloproteinase domain containing protein-10 (ADAM-10), constitutes an immune escape mechanism that impairs NK cell recognition [33], we next determined the ADAM-10 level in MDA-MB-231, RT-R-MDA-B-231, and CD24−/low/CD44+ cells. This evidence concerns the gene KLRK1 and cancer.