IDH1 and glioblastoma: MGMTp methylation is a well-established favorable prognostic marker for survival and predicts the response to temozolomide in patients with GBM.28,42 Since PDGFRA gain/amplification and unmethylated MGMTp were independent prognostic markers, we investigated the potential interaction between PDGFRA gain/amplification and unmethylated MGMTp in patients with GBM and hypothesized that these markers improved the risk stratification of IDH wild-type GBM.