Tumor cells also secrete a variety of inhibitory molecules such as transforming growth factor-β (TGF-β), IL-6, prostaglandin E2, chemokine ligand 2, and colony-stimulating factor 1, which may directly inhibit the expression of CD8+ T cells or promote the accumulation of various immunosuppressive cells. The gene discussed is TGFB1; the disease is neoplasm.