Although a good response was observed in our cell lines with TAK-733, an allosteric MEK1/MEK2 inhibitor, as previously observed in other cutaneous melanoma cell lines in vitro and in vivo [47], in a phase I clinical study in 41 patients including 12 with metastatic uveal melanoma and five with metastatic cutaneous melanoma, a modest response rate (5%) was observed with only two patients with cutaneous melanoma experiencing a partial response rate [48]. This evidence concerns the gene MAP2K1 and cutaneous melanoma.