CEACAM5 and neoplasm: The expression of gastric tumor markers CEA, Ck-7, E-cadherin, and CA 19-9 was evaluated by immunohistochemistry (Fig 1A and 1B) and flow cytometry (Fig 1C) in explant tissues of diffuse and intestinal-subtype gastric adenocarcinomas and in adjacent non-tumor gastric tissues, encompassing the different layers of the stomach wall, including mucosa, submucosa, and muscularis propria.