The expression of nine mRNAs (ABCB1, CXCR4, MAF, MARCKS, POMP, PSMB5, RPL5, TXN, and XBP1) was determined in all 73 MM patients treated with bortezomib-based regimens and the 11 non-MM controls. The gene discussed is PSMB5; the disease is Miyoshi myopathy.