BRAF V599E Mutation is Not Age Dependent: It is Present in Common Melanocytic Nevi in Both Children and Adults

Abstract

BRAF encodes a serine‐threonine kinase, which acts in the RAS/RAF/MAPK pathway transducing regulatory signals from RAS to MEK1/2. Somatic mutations in BRAF have been identified in 53–80% of primary melanomas and 70–90% of common melanocytic nevi. More than 90% of these mutations consist of a valine to glutamate substitution at codon 599 (V599E) of exon 15. While a high prevalence of BRAF mutations in common melanocytic nevi has been reported in adults, nevi in children have not been studied. Of interest, we have previously shown that Spitz nevi in children do not harbor mutations in BRAF. To investigate the association of BRAF mutations with patient age, we studied common melanocytic nevi in children for the V599E activating mutation. Tumor cells were microdissected from 6 common melanocytic nevi in children 10 years of age or younger, and analyzed for the V599E mutation in BRAF by allele‐specific PCR and gel electrophoresis. In 6 of 6 (100%) nevi, the V599E mutant allele was observed. Our data suggest that similar genetic pathways are involved in the development of common melanocytic nevi in children and adults. The absence of BRAF mutations in Spitz nevi in children is therefore associated with tumor type, not patient age.