Conversely, when HDAC inhibitors were combined with TRAIL (a combination that had proved very effective in sensitising CLL cells isolated from patient samples resistant to rhTRAIL (MacFarlane et al, 2005)), in the same organotypic culture conditions used for TRAIL treatment alone, significant hepatotoxicity was observed for the combination (Volkmann et al, 2007). Here, HDAC9 is linked to B-cell chronic lymphocytic leukemia.