However, the incidence of melanoma was lower in Tyr::CreER::NrasQ61K::Ink4a−/− mice used in the present study (50% penetrance, of which 50% of the tumors were confirmed to be melanoma), probably because expression of mutant NRAS was induced only after birth, as opposed to activation of NRAS during embryogenesis, as reported in [39]). This evidence concerns the gene CDKN2A and melanoma.