Early and mature endothelial progenitors and VEGFR2+-cells in multiple myeloma: Association with disease characteristics and variation in different cell compartments

We analyzed (1) early endothelial progenitors (EPCs; CD34+/AC133+/VEGFR2+), mature EPCs (CD34+/VEGFR2+) and VEGFR2+-cells in bone marrow (BM)-specimens of multiple myeloma (MM)- vs. monoclonal gammopathy (MGUS)-patients and healthy controls; (2) differences of BM-, peripheral blood (PB)- and leukapheresis (LP)-samples; and (3) the association of EPCs and VEGFR2+-cells with MM-parameters. MM patients demonstrated highest early and mature EPCs and VEGFR2+-cells in the BM, particularly with advanced and active disease. Endothelial cells differed in BM-, PB- and LP-specimens, albeit seemed less associated with unfavorable prognostic MM-parameters. Our data suggest that especially VEGFR2+-cells and mature EPCs in MM are of value to explore further.