PIK3CA and optic nerve glioma: Additionally, mutations in PIK3CA and NF1—associated with alterations in lipid metabolism and the activation of glycolysis through the RAS signaling pathway, respectively—are frequently linked to glioblastoma, glioma WHO grade IV [54,55] but rare in lower-grade gliomas except for NF1 alterations in pediatric optic nerve gliomas [56].