['Gastrokine 1 (GKN1) plays an important role in the gastric mucosal defense mechanism and also acts as a functional gastric tumor suppressor. The specific aim of this study was to determine the molecular mechanisms underlying GKN1 tumor suppressor activity in the progression of gastric cancers.', 'We examined the effect of GKN1 on epithelial-mesenchymal transition (EMT) and cell migration in GKN1-transfected and recombinant GKN1-treated AGS gastric cancer cells using in vitro wound healing, microchemotaxis, and invasion assays.', 'In GKN1-transfected AGS cells, we observed inhibition of cell migration and invasion in wound healing, transwell and Matrigel assay. Also, GKN1-transfected and recombinant GKN1-treated AGS cells showed decreased levels of ROS and expression of phosphatidylinositol 3-kinase (PI3K)/Akt pathway proteins, concomitant with re-expression of E-cadherin and decreased expression of cytoplasmic and nuclear expression of β-catenin, slug, snail, fibronectin, and vimentin.'] Does gastrokine 1 function as a tumor suppressor by inhibition of epithelial-mesenchymal transition in gastric cancers?