PIK3CA and glioblastoma: Other genetic alterations within the PI3K–AKT–mTOR pathway, such as mutations in phosphatidylinositol‐4,5‐bisphosphate 3‐kinase catalytic subunit alpha (PIK3CA) and phosphoinositide‐3‐kinase regulatory subunit 1 (PIK3R1), are also prevalent in GBM and contribute to its aggressive phenotype [17].