IL10 and cancer: Cytokines formed by tumor cells or immune microenvironment play a key role in the interaction in which immunosuppressive cytokines, such as interleukin-10 (IL-10), prostaglandin E2 (PGE2), transforming growth factor-β (TGF-β), and vascular endothelial growth factor (VEGF) are involved in cancer growth, proliferation and invasion.