MTOR and central nervous system cancer: In gliomas, the consequences of the incorrect expression of these genes is the activation of key signaling pathways responsible for cell survival: RAS-RAF-MEK-ERK (RAS—Ras protein; RAF—rapidly accelerated fibrosarcoma; MEK—mitogen-activated protein kinase; ERK—extracellular signal-regulated kinase) and PI3K-AKT/PKB-mTOR (PI3K—phosphoinositide 3-kinase; AKT/PKB—protein kinase B; mTOR—mammalian target of rapamycin kinase).