As shown in Figure 5A, RAC1 amplification appeared to be more common in metastatic melanoma lesions in three independent cohorts, accounting for 21.875% of cases in MSK-NEJM 2014 (metastatic, n = 64) [41], 13.16% in metastatic melanoma (UCLA, 2016 (n = 38)) [42], and 6.36% in DFCI metastatic melanoma (n = 110; Science 2015) [43] than in primary melanoma. This evidence concerns the gene RAC1 and metastatic melanoma.