V600E BRAF Mutation in Pilocytic Astrocytoma is Associated with a More Diffuse Growth Pattern but Does Not Confer a More Aggressive Clinical Behavior

Activation in mitogen activated protein kinase signaling pathway has recently been described as a predominant event in pilocytic astrocytoma (PA) and is commonly caused by constitutively active mutation in BRAF protein. Whereas PA of posterior fossa in children have a high prevalence of BRAF duplication and fusion, primary molecularm abnormalities in supratentorial tumors of adults are more diverse and also include BRAF V600E point mutation. In our study we evaluated 51 PAs for BRAF duplication and BRAF V600E point mutation. We found a relatively high frequency of V600E mutation in our cohort. Histologically, V600E-carrying PA appeared more infiltrative, yet our limited clinical follow-up failed to detect a deleterious prognostic significance.