MITF-E318K was observed not only in familial and multiple CM cases, in association or not to concurrent pathogenic variants of the Cyclin Dependent Kinase Inhibitor 2A gene (CDKN2A), but also in sporadic cases, and in some CM cases showing association to other cancer types [21,24,27,28,29]. The gene discussed is CDKN2A; the disease is cutaneous mastocytosis.