NRAS and cutaneous mastocytosis: Similarly, a poor prevalence of mutations into the Q61 codon of the NRAS exon 3, which is found in nearly all RAS-mutated CM cases, has been observed in MM; conversely, the G12 and G13 codons within the exon 2 of the gene are maximally involved in NRAS-mutated MM cases [29,30,31].