Inflammatory mediators, such as cyclooxygenase-2 (COX-2)-derived prostaglandin E2 (PGE2), also have been reported as an important factor for cancer progression and contribute to the redirection of the differentiation of dendritic cells into myeloid-derived suppressor cells [5], recruitment of monocytes/macrophages to tumor sites, and inducing them to differentiate into M2-type tumor-associated macrophages to support tumor angiogenesis and invasion [6, 7]. The gene discussed is PTGS2; the disease is cancer.