IDH1 and glioblastoma: Remarkably, as observed in the UTHealth cohort, the PFS (11.0 vs 7.4 months, P = .0237) and OS (34.7 vs 16.6 months, P = .0168) of RB1-mutant patients differ dramatically from KDR-amplified GBM IDH-WT (Figure 2C and D).