Bone marrow angiogenesis in patients achieving complete response after stem cell transplantation for multiple myeloma

Although most of the initial studies in angiogenesis were done on solid tum ors, there is now data suggesting the importance of angiogenesis in hematol ogic malignancies. We estimated bone marrow microvessel density before auto logous stem cell transplantation and at the time of response in 13 patients with myeloma (seven complete and six partial responders) using an immunohi stochemical stain for factor VIII-related antigen (von Willebrand factor). Baseline microvessel density was significantly different between bone marro w samples from patients with myeloma and morphologically normal, staging ma rrows from patients with limited stage Hodgkin's disease, mean (+/- s.d.) 2 94 (+/-115)/mm(2) vs 93 (+/-26)/mm(2), respectively, P = 0.001. After trans plantation, microvessel density continued to be high in myeloma samples com pared to samples from control patients with limited stage Hodgkin's disease , mean (+/- s.d.) 230 (+/-68)/mm(2), P = 0.003. There was no difference in microvessel density at the time of complete or partial response compared to values prior to transplantation. This report confirms that increased angio genesis is found in myeloma bone marrow prior to transplantation, and sugge sts that increased angiogenesis persists even after complete response.