IDH1 and central nervous system cancer: Another important achievment in GBM epigenomics is the identification of glioma-CpG island methylathor phenotype (G-CIMP), which has provided the basis for subsequent epigenomic studies [11, 24] focused on epigenetic differences to classify diffuse IDH mutant and IDH-wild-type gliomas into further molecular subgroups with characteristic patient outcome.