MTOR and nervous system neoplasm: Current clinical trials are investigating targeted therapy focusing on the mitogen-activated protein kinase pathway and the mammalian target of the rapamycin (mTOR) pathway.9–13 The most common genetic alterations in pLGGs are BRAF fusion (KIAA1549-BRAF) and BRAF V600 E mutation.14 A study analyzing BRAFV600E in 1320 nervous-system tumors found that rather than BRAF fusion, BRAF V600E seems to be more frequent in extra-cerebellar pilocytic astrocytoma than in cerebellar tumors, especially in the diencephalic region (33%).15