To investigate the effect of NK inhibitory receptors on the observed cytotoxic efficacy, the expression levels of KIR2D and NKG2A on the NK cells, and of their respective ligands, i.e., HLA-ABC/-G and HLA-E [37], on the cervical cancer cell lines, were assessed (Fig. 4a, b). The gene discussed is KLRC1; the disease is cervical cancer.