HDAC9 and breast cancer: However, the knockdown of HDAC11 using short hairpins RNA (shRNAs), as well as global inhibition of HDACs using vorinostat and entinostat which are not HDAC11-specific, led to increased distant metastasis from LNs in vitro and in vivo, suggesting the involvement of other HDACs and taking caution with the single-agent use of HDAC inhibitors during BC treatment.