Interestingly, we found that alteration of HDAC expression in bortezomib-resistant myeloma cells is heterogeneous, such that HDAC3, 4, 5, 7, 9, 10, and 11 are downregulated while HDAC2 and 6 are upregulated [Figure 1B]. The gene discussed is HDAC9; the disease is plasma cell myeloma.