Increased angiogenesis has been recently reported in acute and chronic leukemias, lymphomas, and myeloproliferative disorders. Endoglin (CD105), a member of transforming growth factor beta (TGF-beta) receptor family, modulates cellular responses to TGF-beta and is absolutely essential for angiogenesis. Its soluble form (sCD105) is increased in patients with various solid tumors. In our pilot study, we measured peripheral blood plasma concentrations of sCD105 using comercially available enzyme-linked immunosorbent assay in 75 patients with lymphoid malignancies and 13 healthy donors. We found a statistically significant increase in sCD105 concentrations in patients with B-cell chronic lymphocytic leukemia (n = 42) compared to the control group (p = 0.0296). Suprisingly, patients with multiple myeloma (n = 13) had significantly lower concentrations of sCD105 in comparison to controls (p = 0.0023). We didn’t find significant differences between sCD105 concentrations in patients with follicular lymphoma (n = 8) or diffuse large B-cell lymphoma (n = 12) and the control group. We conclude that plasma sCD105 is a new angiogenesis marker in lymphoid malignancies and together with other cytokines (such as VEGF - vascular endothelial growth factor and bFGF – basic fibroblast growth factor) might be useful as a part of complex angiogenesis assessment aimed to improve prognostic stratification of these disorders.

        Key words: endoglin, CD105, angiogenesis, myeloma, lymphoma, B-CLL