Immunohistochemical stainings of tight junction-related proteins in esophageal mucosa. Occludin, Claudin-1, -2 and ZO-1,-2 are displayed by brown or red staining, respectively. Panels illustrate representative staining for controls and samples obtained from patients with NERD. Immunohistochemical staining was observed in the esophageal squamous epithelium mainly at the basal and suprabasal zone. Claudin-1/2 and ZO-1 showed partly a membranous staining. (Zeiss Axioskop 50; camera: Nikon coolpix 990).