CREB1 and mucinous neoplasm: In this study, we investigated the impact of inhibiting Prostaglandin E2 (PGE2)/ G-protein coupled E-type prostanoid receptor 4 (EP4)/ cyclic AMP (cAMP)/ protein kinase A (PKA)/ cAMP response element binding protein (CREB) signaling pathway on MUC2 protein production and mucinous tumor growth using in vitro models of mucinous appendix cancer/PMP, as well as a unique in vivo murine intraperitoneal patient-derived xenograft (PDX) model of PMP, developed in our laboratory [16].