STAT3 and neoplasm: In tumor cells, over-activated STAT3 decreases the expression of immunostimulatory factors, including pro-inflammatory cytokines (IL-12, TNF-α), IFN and chemokines (CCL5, CXCL10), while increasing the expression of certain cytokines (IL-6, TGF-β, and VEGF), thus playing an immunosuppressive effect.