SDC1 and plasma cell myeloma: IGFBP7 gene expression levels were significantly decreased in a series (HM group) of CD138 sorted plasma cells from MGUS (n = 22) and MM patient samples (n = 332) as well as in human myeloma cell lines (HMCLs) (n = 32) compared to normal plasma cells (n = 10) (P < 0.02) whereas IGFBP7 expression was absent in memory B cells (MBCs) and proliferating polyclonal plasmablastic cells (PPCs) (Figure 1A).