PTGER4 and pancreatic neoplasm: Knockout (KO) of Ptges (the gene encoding the PGE2 synthesis enzyme mPGES-1) or the EP4 receptor gene (Ptger4) in KPCY (KrasG12DP53R172HYfpCrePdx) pancreatic tumor cells abolished growth of implanted tumors in a T cell–dependent manner.