IDH1 and neoplasm: Previously, smaller studies had already provided evidence for the importance of enhancers and bivalent promoters for subtype identity42,43; however, these studies used RNA transcription-based subtype classification schemes that did not differentiate between IDHwt and IDH-mutated proneural-subtype tumours, or included the meanwhile abandoned concept of a “Neural” subtype of glioblastoma2,4.