We hypothesized that combining an HDAC inhibitor and an EZH2 inhibitor would be synergistic by targeting epigenetic mechanisms (i.e., histone deacetylase and histone methyltransferase), whereby EZH2 inhibitors remove H3K27me3 to allow for acetylation of H3K27, which could be beneficial to proneural glioma patient prognosis [56]. This evidence concerns the gene HDAC9 and glioma.