Angiogenesis has been measured using microvessel density. In a prior study, we have demonstrated increased microvessel density using CD34 immunohistochemistry in patients with multiple myeloma, compared to SMM or MGUS, suggesting that there is increased vascular density as the disease progresses. A correlation between MM disease stage and prognosis has been reported for several serum angiogenic factors and myeloma cells and bone marrow endothelial cells have been shown to secrete and respond to angiogenic modulators.