Immunohistochemical expression of endoglin offers a reliable estimation of bone marrow neoangiogenesis in multiple myeloma

Purpose The aim of the present study was to evaluate CD105 tissue marker in the bone marrow (BM) of multiple myeloma (MM) patients. CD105 was evaluated using immunohistochemical method. An effort was made to correlate this marker with BM microvascular density (MVD) along with other known markers of angiogenesis in order to evaluate its clinical significance. Methods BM MVD was estimated by CD31. CD105 in BM was estimated by immunohistochemical method in 54 newly diagnosed patients with MM. Circulating levels of known angiogenic factors such as basic fibroblast growth factor (b-FGF) and soluble CD105 (sCD105) were measured by ELISA in the same group of patients. All these factors were also measured in 20 age- and sex-matched healthy controls. Results We found that CD105 MVD, along with the expected CD31 MVD, and serum levels of sCD105 and bFGF were increased, also in parallel with disease stage, and all were decreased after effective treatment. Moreover, CD105 MVD correlated with all the aforementioned markers of angiogenesis. Conclusions Our results indicated that CD105 MVD is following the behavior of CD31 MVD in MM, suggesting being a valid marker of BM neoangiogenesis in MM. Its prognostic impact remains to be proven.