HDAC9 and cancer: Success of proteasome inhibitors such as bortezomib and carfilzomib has provided support to the idea that the ubiquitin-proteasome system, a component of protein homeostasis, could be targeted in cancer.1,2 Likewise, effectiveness of compounds such as Hsp90 inhibitors,3 autophagy modulators,4 and HDAC inhibitors5 in several cancer types further support this idea.