HDAC9 and prostate cancer: While, for prostate cancer, 5 out of 11 drugs have at least one diffEnhancer associated with drug perturbational genes, and potent Histone Deacetylase (HDAC) inhibitor ‘Trichostatin A’ had about 62% (146/235) diffEnhancers with their TGs also displaying significantly different expression level after ‘Trichostatin A’ treatment (Fig. 4c).