IL6 and neoplasm: In many studies, MDSCs have different immunosuppressive pathways to facilitate tumor development such as suppressing effector T (Teff cells) cells and inducing regulatory T (Treg) cells or regulatory B cells under certain conditions [10, 12], and some tumor-derived factors such as CSF-1, IL-6, IL-10, VEGF, and GM-CSF could influence recruitment of the MSCs at tumor site [14].