Adverse Prognostic Impact of Bone Marrow Microvessel Density in Multiple Myeloma

5 , Translational Epidemiology Branch, National Cancer Center, Goyang, Korea Background: Angiogenesis is important for the proliferation and survival of multiple my- eloma (MM) cells. Bone marrow (BM) microvessel density (MVD) is a useful marker of angiogenesis and is determined by immunohistochemical staining with anti-CD34 anti- body. This study investigated the prognostic impact of MVD and demonstrated the rela- tionship between MVD and previously mentioned prognostic factors in patients with MM. Methods: The study included 107 patients with MM. MVD was assessed at initial diagno- sis in a blinded manner by two hematopathologists who examined three CD34-positive hot spots per patient and counted the number of vessels in BM samples. Patients were di- vided into three groups according to MVD tertiles. Cumulative progression-free survival (PFS) and overall survival (OS) curves, calculated by using Kaplan-Meier method, were compared among the three groups. Prognostic impact of MVD was assessed by calculat- ing Cox proportional hazard ratio (HR). Results: Median MVDs in the three groups were 16.8, 33.9, and 54.7. MVDs were corre- lated with other prognostic factors, including β2-microglobulin concentration, plasma cell percentage in the BM, and cancer stage according to the International Staging System. Multivariate Cox regression analysis showed that high MVD was an independent predictor of PFS (HR=2.57; 95% confidence interval, 1.22-5.42; P =0.013). PFS was significantly lower in the high MVD group than in the low MVD group (P =0.025). However, no differ- ence was observed in the OS (P =0.428). Conclusions: Increased BM MVD is a marker of poor prognosis in patients newly diag- nosed with MM. BM MVD should be assessed at the initial diagnosis of MM.