IDH2 and brain neoplasm: The diagnosis of brain tumours is achieved by combining morphological features, immunohistochemical (IHC) detection of lineage-related markers, and more recently by the detection of genetic biomarkers, for example mutations in the isocitrate dehydrogenase genes 1 and 2 (IDH1 and IDH2) [1, 13], BRAF [35], or histone genes [16].