CD274 and meningioma: To assess whether the PI3K–AKT–mTOR pathway regulates PD‐L1 expression in NF2 meningiomas, NF2‐associated meningioma cells were treated with inhibitors of PI3K (LY294002, 50 μmol/L), AKT (MK‐2206 2HCL, 5 μmol/L), and mTOR (rapamycin, 2 μmol/L).