Detecting Laryngopharyngeal Reflux by Immunohistochemistry of Pepsin in the Biopsies of Vocal Fold Leukoplakia

Laryngopharyngeal reflux (LPR) may contribute to the development of laryngeal diseases including vocal fold leukoplakia. Clinical methods of determining LPR are limited. Pepsin, as an exogenous protein, is considered as a biomarker of LPR. The aim of the current study was, therefore, to detect pepsin by immunohistochemistry in the biopsies from patients with vocal fold leukoplakia, and by which, to determine the potential association of LPR and vocal leukoplakia. A total of 26 biopsies from patients with vocal fold leukoplakia were examined in comparison with 20 vocal fold biopsies from control subjects. We found that 2 out of 26 patients (7.7%) were strongly positive, 4 of the 26 (15.4%) patients were positive, 11 of the 26 (42.3%) patients were weakly positive, and 9 of the 26 (34.6%) were negative staining for pepsin. In contrast, only 4 of the 20 (20.0%) control subjects were weakly positive and the rest (16; 80.0%) were negative staining for pepsin. There was significant difference between the two groups in terms of positivity of pepsin staining (chi(2)=24.181, P<0.001). These findings suggest that pepsin immunohistochemical staining could be a biomarker of LPR and that LPR may be a risk factor for the development of vocal fold leukoplakia.