Induction of in vitro angiogenesis. Endothelial cell growth in the AngioKit model. (A) Box plot summarizing the ELISA results. Unlike those of MBC supernatants of BMPCs, pMMCs and HMCLs show a significant induction of tubule formation compared with medium control. *Significant difference compared with medium control (P < .05). (B) Immunostaining with monoclonal anti-human CD31 antibody: medium control (RPMI 1640), positive control (VEGF), negative control (suramin) as well as supernatants of memory B-cell samples (MBC1-3), normal bone marrow plasma cell samples (BMPC1-3), primary myeloma cell samples (pMMC1-3), and the myeloma cell lines SKMM-2, XG-10, and U266. Original magnifications ×40.