HDAC9 and glioblastoma: To this end, histone deacetylase (HDAC) inhibitors, such as MS27519, SAHA20, Valproic acid21, Depsipeptide22, SBHA23, LAQ82424 have been shown to augment TRAIL responses in various tumor types including prostate cancer, primary myeloid leukemia, melanoma, breast cancer, medulloblastoma, CLL, and GBM.