Rare in adults, 2nd most common malig in children and 1st cause of death from malig , 1500 / y in CZ (100 children) / 2 age peaks : <5y and >65y / mostly sporadic, radiation exp, 10% familial (LiFrameni, Neurofibromatosis, Turcot sy) / Gliomas: diff astro, pilocytic astro, oligodenro, ependy, choroid plx tu - Embryonal - Glioneural - meninge - other