The triggering of ADCC detected using Ipilimumab with ex-vivo NK cells and CTLA-4+ melanoma targets was conceivably due to the binding of Ipilimumab to FcγRIIIA expressed on NK cells as the addition of an anti-FcγRIIIA antibody to the assay could almost block the ADCC (Figure 4B, P < 0.0001). This evidence concerns the gene CTLA4 and melanoma.