MTOR and glioblastoma: Recent reports on the addiction of GBM to IMPDH [12,60] triggered our interest in further dissecting the anti-tumor effect of IMPDH inhibition on several key oncogenic drivers in adult primary GBM [31], including increased expression of MGMT and TERT [61,62], EGFR amplification [63], PTEN deletion/mTOR dysregulation [64], and homozygous CDKN2A deletion [65].