An analysis of a large dataset of around 1000 samples of paediatric and adult gliomas revealed that K27M and G34R/V H3.3 variants represent different biological subgroups (Mackay et al., 2017); K27M H3.3 tumours are found in 70% of DIPG and non-brainstem midline paediatric gliomas and exhibit selective mutations in CCND2 and TOP3A, whereas H3.3G34R/V-mutant tumours are restricted to the cerebral hemispheres and co-segregate with mutations in the histone-associated proteins ATRX and TP53. Here, ATRX is linked to neoplasm.