Clinicopathological characteristics associated with BRAF(K601E) and BRAF(L597) mutations in melanoma.

BRAF mutations at codons L597 and K601 occur uncommonly in melanoma. Clinical and pathological associations of these mutations were investigated in a cohort of 1119 patients with known BRAF mutation status. A BRAF mutation was identified in 435 patients; Mutations at L597 and the K601E mutation were seen in 3.4 and 3.2% of these, respectively. K601E melanomas tended to occur in male patients, a median age of 58 yr, were generally found on the trunk (64%) and uncommonly associated with chronically sun-damaged (CSD) skin. BRAF L597 melanomas occurred in older patients (median 66 yr), but were associated with CSD skin (extremities or head and neck location - 73.3%, P = 0.001). Twenty-three percent of patients with V600E- and 43% of patients with K601E-mutant melanomas presented with nodal disease at diagnosis compared to just 14% of patients with BRAF wild-type tumors (P = 0.001 and 0.006, respectively). Overall, these mutations represent a significant minority of BRAF mutations, but have distinct clinicopathological phenotypes and clinical behaviors.