HDAC9 and glioblastoma: We identified multiple hits, and further evaluated the therapeutic potential of compounds regulating two epigenetic modifiers, enhancer of zeste homolog 2 (EZH2) and histone deacetylase (HDAC), both of which have high relevance for GBM.EZH2 as well as HDAC1 and HDAC2 are over-expressed in GBM [19–23] and are associated with shorter overall survival [19, 20, 22].