Tumor-derived cytokines and growth factors such as VEGF, IL-6, granulocyte CSF, granulocyte-macrophage CSF, and other proinflammatory mediators such as IL-1β, IL-17, HMGB1, cyclooxygenase 2 (COX2), and prostaglandin E2 (PGE2) induce MDSCs accumulation, differentiation, proliferation, and acquisition of immunosuppressive functions (80, 81). The gene discussed is PTGS2; the disease is neoplasm.