HDAC9 and neoplasm: A previous study on dual-acting COX-2/HDAC inhibitors as MTDs based on celecoxib and indometacin as COX-2 binding motif and a hydroxamic acid moiety as HDAC binding motif demonstrated cell growth inhibition in different tumor cell lines (breast, non-small cell lung, colon, androgen-dependent and -independent prostate cancer) that outmatched combinations of vorinostat with either celecoxib or indometacin [35].