Growth factors, such as vascular endothelial growth factor (VEGF) and TGF-β, in addition to a variety of cytokines, including IL-6, IL-17, IL-10, granulocyte-macrophage colony-stimulating factor (GM-CSF), and leukemia inhibitory factor (LIF), produced by both stromal and tumor cells, promote STAT3 activation. The gene discussed is CSF2; the disease is neoplasm.