In addition, BRAF V600E IHC analysis allows identification of tumor cells at the single cell level, which would not only aid in the diagnosis of biopsies with very low tumor cell content but would also allow localization of the mutation at a cellular type level, as recently highlighted by the demonstration of neuronal tumor cells as the predominant tumor cell population harboring the BRAF V600E mutation in gangliogliomas [15]. The gene discussed is BRAF; the disease is ganglioglioma.