HDAC9 and plasma cell myeloma: Furthermore, we show that this model is suitable for the assessment of response to therapy with drugs known to be efficacious against myeloma, bortezomib (BZB), and melphalan, and two novel agents, an aminopeptidase inhibitor and a HDAC inhibitor which we have previously shown to be effective in vitro, and which has recently shown efficacy in a phase I/II trial in acute myeloid leukaemia and myeloma [13], [14].