Increased COX-2 Expression of Esophageal Squamous Epithelium in the Patients with Reflux Esophagitis

Abstract

Background/Aims: Reflux-induced injury and oxidative stress result in esophageal inflammation and the potential for progression to intestinal metaplasia and adenocarcinoma. Previous studies have suggested that increased expression of COX-2 is important in the genesis of esophageal adenocarcinoma. The aim of this study was to compare the COX-2 expression of distal esophageal squamous epithelium between the patients with reflux esophagitis and normal controls. Methods: Biopsies of the distal esophageal squamous mucosa were taken 3 cm above the squamocolumnar junction in 19 reflux esophagitis patients and 21 normal controls. The expression of COX-2 was confirmed by immunohistochemistry using monoclonal antibodies. The staining index was obtained by adding up the scores for staining intensity with the staining area, which ranged from 0 to 6. Results: COX-2 expression in the squamous epithelium from paraffin embedded biopsies in patients with reflux esophagitis was significantly increased compared to controls (31.6% vs. 0%, P = 0.038). The mean COX-2 expression score was 2.2 in the reflux esophagitis patients with positive COX-2 expression. Conclusions: It suggests that the changes in COX-2 expression occur before any metaplastic changes in the esophageal squamous epithelium of the patients with reflux esophagitis.