Intratumoral injection of paclitaxel loaded MSCs to nude mice with subcutaneous acute lymphoblastic leukemia resulted in a reduction of tumor vascularization, microvascular density, and expression of angiogenic markers such as von Willebrand factor, CD31 (PECAM1), VEGF-α, Ve-cad, TGF-β1, CD44, and αSMA. This evidence concerns the gene PECAM1 and neoplasm.