IL6 and neoplasm: Suppressive immune cells including polymorphonuclear (PMN)-myeloid-derived suppressor cells (MDSCs), monocytic (M)- MDSCs, tumor-associated macrophages (TAMs), and regulatory T cells (Tregs),and cytokines or small molecules released by these cells such as TGF-β, interleukin (IL)-10, IL-6, or vascular endothelial growth factor (VEGF), are also involved in the suppressive microenvironment in tumor sites5–8.