KLRK1 and breast carcinoma: Besides, the overproduction of ROS can attenuate the phosphorylation of eukaryotic initiation factor 2B, downregulate the expression of natural killer group 2 member D (NKG2D) and NKG2D ligands, and subsequently reduce the release of cytotoxic granules of NK cells, thus suppressing NK cell-mediated antibody-dependent cell-mediated cytotoxicity activity and finally promoting breast cancer growth and metastasis 7, 55.