SDC1 and plasma cell myeloma: To determine the expression of thioredoxin in bortezomib relapsed/refractory myeloma patients, we isolated CD138+ cells and CD138− cells from untreated newly diagnosed myeloma patients (n = 3), myeloma patients who have just completed bortezomib containing regimen induction therapy with residual myeloma cells (n = 5), and relapsed/refractory myeloma patients (n = 5) who had previous exposure and resistant to bortezomib.