HDAC9 and posterior cortical atrophy: In this study, we reported a novel finding that docetaxel‐induced CRPC chemo‐resistant cells were hyper‐acetylated, and an HDAC inhibitor TSA induced resistant cell death via caspase‐dependent apoptosis with IC50 at 0.33 ± 0.06 μM compared with the paired PCa cells (2.87 ± 0.21 μM).