IDH1 and glioma: To investigate the extent of variability in gene expression of IDH-WT gliomas, we performed unsupervised clustering of merged TCGA low-grade glioma (LGG-TCGA) and glioblastoma (GBM-TCGA) gene expression datasets comprised of 3903 differentially expressed genes for 238 IDH-WT gliomas and 5 normal brain control tissues, as depicted in Fig. 1.