IDH1 and glioblastoma: In the Brennan et al’s study profiling 332 GBM tumors, 5 out of 30 IDH-mutant GBM cases were identified to be EGFR-amplified (16.7%), all of which were G-CIMP-high, with 2 out of 5 containing MYC amplification and/or CDKN2A/B loss.5 (Table 1).