Although TSA has been shown to confer anti-cancer effects in vitro and in vivo (Marks et al., 2001; Zhu and Otterson, 2003; Mukhopadhyay et al., 2006), cancer treatments using HDAC inhibitors can be inefficient due to their instability and low retention in vivo (Monneret, 2005). This evidence concerns the gene HDAC9 and cancer.