E-cadherin but not beta-catenin expression is decreased in laryngeal biopsies from patients with laryngopharyngeal reflux.

Abnormal exposure of acid refluxate on the esophageal mucosa has been shown to decrease the epithelial barrier function through an alteration in the intercellular junctional complex. However, only few studies have examined the molecular effects caused by abnormal exposure of gastric refluxate on the laryngeal epithelium. E-cadherin and beta-catenin are cell membrane-associated proteins playing a major role in the maintenance of cell-cell adhesion in epithelial tissues. In this study we tried to analyse the molecular effect of laryngopharyngeal reflux (LPR) on the cellular expression of these proteins. Therefore, we compared the expression of E-caherin and beta-catenin in laryngeal biopsies from patients with and without pH-documented laryngopharyngeal reflux. Paraffin-embedded archival laryngeal biopsies taken from 21 patients, who had undergone rigid laryngoscopy under general anaesthesia and postoperative 24-h pH monitoring, were evaluated immunohistochemically with antibodies to E-cadherin and beta-catenin. The membrane expression of the two proteins was categorized in no expression, mild, moderate and strong (grade 0-3). In LPR patients (n=14) the mean grade of E-cadherin and beta-catenin expression was 1.57 and 1.21, while in specimens of patients without pH-documented LPR it was 2.57 and 1.29. The difference in E-cadherin expression was statistically significant (P=0.011). From our findings we conclude that LPR can cause a decrease in the laryngeal expression of E-cadherin but not of beta-catenin. The reduction of E-cadherin-mediated adhesion could contribute to the development of laryngeal neoplasms. E-cadherin immunostaining of laryngeal biopsies could be a further diagnostic tool to confirm the diagnosis in patients with suspected LPR.