NRAS and melanoma: RAC1 is a RAS-related GTPase that regulates cell proliferation and migration [10,11]; RAC1P29S is a recurrent UV-signature mutation in cutaneous non-acral melanomas and was the third most frequent activating mutation (9.2%) after those of BRAF and NRAS in a large cohort (n=147) of exome-sequenced melanomas [11].