Research ArticlesExpression of Proteinase-activated Receptor-2 in the Esophageal Mucosa of Gastroesophageal Reflux Disease Patients A Histomorphologic and Immunohistochemical StudyAbd El-Rehim, Dalia M. PhD*; Fath El-Bab, Hanaa K. MD†; Kamal, Enas M. MD†Author Information Departments of *Pathology †Tropical Medicine, Faculty of Medicine, Minia University, El-Minia, Egypt The authors declare no conflict of interest. Reprints: Dalia M. Abd El-Rehim, PhD, Department of Pathology, Faculty of Medicine, Minia University, El-Minia 61111, Egypt (e-mail: [email protected]). Received April 8, 2014 Accepted July 13, 2014 Applied Immunohistochemistry & Molecular Morphology: October 2015 - Volume 23 - Issue 9 - p 646-652 doi: 10.1097/PAI.0000000000000130 Buy Metrics Abstract Data are limited regarding the role of proteinase-activated receptor-2 (PAR-2) in the esophageal mucosa in gastroesophageal reflux disease (GERD) patients. Our aim was to study PAR-2 expression and its relationship with different GERD-related clinical and pathologic parameters. Histomorphologic alterations in eosophageal mucosa in nonerosive reflux disease (NERD) and erosive reflux disease (ERD) were also, evaluated. Endoscopic biopsies of the esophageal mucosa were obtained from 94 GERD patients and 20 participants for histopathologic analysis and PAR-2 immunohistochemical staining. The present study demonstrated significantly higher PAR-2 expression in GERD patients compared with control, whereas no significant differences were seen between NERD and ERD groups. PAR-2 expression significantly correlated with histologic score (r=0.572, P<0.001) and severity of heartburn (r=0.541, P<0.001). PAR-2 expression was significantly associated with basal cell hyperplasia, and dilated intercellular spaces and inflammatory cell count (P<0.05). Histologic analysis revealed GERD-related histomorphologic alterations in the esophageal mucosa of GERD patients with significant differences (P<0.05) among groups. Total histologic score was significantly correlated with heartburn (r=0.299, P=0.025) and endoscopic severity (r=0.359, P=0.027) in NERD and ERD patients, respectively. Taken together, this study provides evidence for the major role of PAR-2 in the pathogenesis of GERD and GERD-associated mucosal alterations. Copyright 2015 Wolters Kluwer Health, Inc. All rights reserved.