Also, MDSCs directly produce angiogenic factors, including VEGF and bFGF, through Stat3 activation to induce angiogenesis, and Stat3-regulated factors produced by MDSCs also induce constitutive activation of Stat3 in tumor endothelium, which is required for tumor factor-induced endothelial migration and tube formation (56). Here, FGF2 is linked to neoplasm.