['To study the effects of ephrinB2 gene transfection on the differentiation of bone marrow mesenchymal stem cells (BMSCs) into vascular endothelial cells.', 'Wistar rat BMSCs were isolated by density gradient centrifugation and purified on the basis of their adhesion ability. The BMSCs were transfected with a lenti-virus vector encoding a constitutively active form of human ephrinB2 gene, and the cell markers including CD105, CD73, CD44, von Willebrand factor (VWF) and vascular growth factor receptor 2 (KDR) were detected using flow cytometry. The potential of ephrinB2-BMSCs for differentiation into osteoblasts and adipoblasts in vitro were tested, and the differentiation of the cells into endothelial-like cells was induced by culture in the presence of 2% fetal bovine serum and 50 ng/ml vascular endothelial growth factor.', 'EphrinB2-BMSCs were positive for the markers CD105, CD73 and CD44, and negative for the typical endothelial markers like VWF and KDR, and retained high potentials for differentiation into osteoblasts and adipoblasts in vitro after cultivation in respective media. After induced differentiation, ephrinB2-BMSCs expressed VWF and KDR and showed greater ability of differentiation into vascular endothelial cells and formation of capillary structures on matrix gel than the BMSCs without transfection.'] Does [ EphrinB2 gene transfection promote the differentiation of bone marrow mesenchymal stem cells into vascular endothelial cells ]?