IL6 and neoplasm: For tumor cells, STAT3 decreases the production of immuno-stimulatory cytokines such as interferon-γ (IFN-γ) and tumor necrosis factor-α (TNF-α), along with elevated expression of immuno-exhausting cytokines (IL-6, IL-10, transforming growth factor-β [TGF-β], and VEGF) [155,156].