PTGES and neoplasm: PLA2G4F, COX-2 and PTGES are important enzymes for the synthesis of its downstream bioactive lipid products, PGE2, which binds to EP2, and act as multiple signaling pathways of modulating various pathophysiological functions in the tumor microenvironment (TME), including chronic inflammation, invasion and metastasis, cell apoptosis angiogenesis, tumor immune evasion and tumor occurrence (31, 32).