IDH1 and cancer: TP53 and RB1 mutation co-occurrence has been previously reported in several cancers.7,27 Also, RB1 exclusivity with EGFR amplification has been demonstrated in GBM xenograft models and glioma patients.7,28 Importantly, we identified for the first time that RB1-mutant GBM IDH-WT had improved PFS and OS than RB1-WT patients after multivariable adjustment (Figure 2 and Table 1).