PTGER1 and colorectal cancer: Consistent with our study, both PGE2 and 20-HETE were shown to activate the epidermal growth factor receptor (EGFR)/PI3K/Akt signaling pathway in colorectal cancer and renal epithelial cells, respectively [51, 52], and stimulated the activation of the PI3K/Akt, MAPK/Erk or GSK3β/β-catenin pathway through binding of prostaglandin E2 receptors (EP)1-4 or G protein-coupled receptors (GPCR), respectively [37, 53].