Interleukin-10 (IL-10) is an anti-inflammatory cytokine with important immunoregulatory functions. It is a cytokine with potent anti-inflammatory properties, repressing the expression of inflammatory cytokines such as TNF-Alpha, IL-6 and IL-1 by activated macrophages IL-10 is a pleiotropic cytokine with important immunoregulatory functions. Its actions influence activities of many of the cell-types in the immune system. It is primarily secreted by antigen-presenting cells such as activated T-cells, monocytes, B-cells and macrophages. In biologically functional form, it exists as a homodimer that binds to tetrameric heterodimer IL-10 receptor and induces downstream signaling. IL-10 is associated with survival, proliferation and anti-apoptotic activities of various cancers such as Burkitt lymphoma, non-Hodgkins lymphoma and non-small scell lung cancer.