Expression of DKK1 gene and protein in normal tissues and myeloma cells. (A) RT-PCR showing DKK1 gene expression in placenta, prostate, uterus, and testis but not in other tissues. (B) RT-PCR showing DKK1 gene expression in all myeloma cell lines and primary tumor cells from 10 patients and in MSCs but not in PBMCs. (C) Western blots showing DKK1 protein expression in most myeloma cell lines and primary tumor cells from all 10 patients. Representative results of 4 independent experiments are shown.