ARID2 and melanoma: (c) A third group of melanomas includes tumors with wild-type NRAS and BRAF, few copy number alterations, and a high number of mutations; among the frequent mutations are those occurring at the level of the gene NF1 (these are inactivating mutations, with possible oncogenic implications given the capacity of NF1 to act as a negative regulator of RAS signaling) and of the tumor suppressors p53, ARID2, and PTPRK and of the RAC1 gene.