EZH2 and diffuse intrinsic pontine glioma: Currently, several classes of drugs have been used in pre-clinical experiments and clinical trials to treat DIPG, such as histone deacetylase and demethylase inhibitors, H3K27 demethylase inhibitor, Zeste enhancer homologue-2 (EZH2) inhibitors, DNA methylation inhibitors, and inhibitors of bromodomain and extra-terminal motif proteins [51,52,53,54,55,56,57,58,59,60].