CCL2 and neoplasm: When the sMSCs were transfected with siRNAs specific for angpt2 or ccl2 before coinjection with tumor cells in mice, the sMSC-induced tumor growth accompanied by increase of F4/80+TIE2+ tumor-associated macrophages (TAMs) or CD11b+Gr1+ MDSCs in the tumor tissues was significantly inhibited.