Patients undergo blood and bone marrow sample collection periodically during study for laboratory correlative studies. Bone marrow plasma samples (i.e., fresh marrow aspirates) are assessed for marrow angiogenesis (microvessel density) by IHC; angiogenic capability (tubular network formation) by in vitro angiogenesis assay; tumor cell proliferation by bromo-2-deoxyuridine uptake; tumor cell apoptosis by three-color flow cytometry (CD38, CD45 or CD138, and 7AAD); and expression of VEGF and soluble VEGF receptors on plasma cells by enzyme-linked immunosorbent assay. Bone marrow biopsies are assessed for various phosphoproteins by IHC; phosphorylation status of ERK1/2 by immunoblotting; and for pharmacodynamic markers (e.g., P70 S6K) by immunoblotting. Blood samples are assessed for surface markers of circulating endothelial cells (CD105, CD34, and CD146) by flow cytometry and for circulating endothelial cell progenitors by late colony formation in mononuclear cells. The endothelial lineage is confirmed by phenotyping of surface markers for endothelial cells.