Tumor-derived cytokines such as IL-6, IL-8, IL-10, CSF-1, CCL2, CXCL2, PGE2 and TGF-β promote MDSC expansion and recruitment,248,249 whereas hypoxia shifts MDSC metabolism toward fatty acid oxidation,250 reinforcing their immunosuppressive properties. The gene discussed is CSF1; the disease is neoplasm.