Meanwhile, we observed that the AOM/DSS induced CAC mice upregulated Ptger2, Pla2g4f and Ptges expression, to increase synthesis of Prostaglandin E2 (PGE2) receptor 2 subtype (EP2), a G protein-coupled receptor, and that PGE2, a downstream arachidonic acid metabolites of COX-2 and prostaglandin E synthase (PTGES), binds to EP2 to mediate multiple intracellular signaling pathways to promote colon cancer development (9, 31, 32). This evidence concerns the gene PTGER2 and malignant colon neoplasm.