Elevated levels of prostaglandin E2 (PGE2) and vascular endothelial growth factor (VEGF) in tumor microenvironment have been identified to induce the expansion of MDSCs [19-21] Over the last few years, it has become appreciated that MDSCs participate in a variety of inflammatory immune responses and accumulate in spleens of mice in various models of immunosuppression [22,23]. Here, VEGFA is linked to neoplasm.