Clinicopathologic findings and BRAF mutation in cutaneous melanoma in young adults.

Abstract

Cutaneous melanoma in young patients is rare with increasing incidence. It is not clear whether the etiology and clinical outcome are similar to cutaneous melanoma in the elderly. Mutations in BRAF gene in patients with cutaneous melanoma, in general, range in frequency from 20% to 80%; however, the status and clinical significance of BRAF mutations in the young population have not been evaluated. We investigated 132 cases of primary cutaneous melanoma in patients aged between 18 and 30 years with emphasis on clinical characteristics, pathologic features, and molecular evaluation of mutation in the BRAF gene (BRAF(V600E)). It was predominantly seen in female individuals (61.4%), trunk was the most common site of involvement (40.4%), and superficially spreading melanoma was the predominant histologic type (79.5%). Mutation in BRAF(V600E) was analyzed successfully in 93 cases using an RT-PCR. The BRAF(V600E) mutation was identified in 38.7% (36/93) and was associated with vertical growth phase (P=0.01) and mild inflammatory infiltrate (P=0.02). No case of melanoma with regression phenomenon presented with BRAF(V600E) mutation (P<0.05). There was no significant association between BRAF(V600E) mutation and sex, histologic type, the Clark level, the Breslow index, solar elastosis, angiolymphatic and perineural invasion, satellitosis, and coexisting nevus. As in melanomas in older patients, these results probably indicate that BRAF mutation may not be the only key factor in melanoma tumorigenesis, and that there should be multiple alternative genetic pathways related to melanoma.