Recent studies of primary melanomas and their adjacent precursor ‘intermediate’ lesions (dysplastic nevi and melanoma in situ) using a multigene targeted sequencing platform have confirmed that DN lack any alterations in the tumor suppressor genes CDKN2A, TP53, NF1, RAC1, and PTEN, that they have UV signature patterns distinct from those of melanoma, and that their overall mutation burden appears to be intermediate between benign nevi and melanoma [16,33]. This evidence concerns the gene RAC1 and melanoma.