Those pilocytic astrocytomas which do not harbour KIAA1549–BRAF fusion mutations, have been found to have mutations in genes encoding constituents of the MAP kinase pathway, including FGFR1 and NTRK gene family, NF1, PTPN11, KRAS and RAF1 [10, 21, 60]. This evidence concerns the gene BRAF and pilocytic astrocytoma.