Gastric H+/K+-ATPase Expression in Normal Laryngeal Tissue and Laryngeal Carcinoma

Yang-Yang Bao,1 Qian Jiang,1 Zhen-Wei Li,1,2 Er Yu,1 Shui-Hong Zhou,1 Hong-Tian Yao,3 Jun Fan,4 Wei-Wei Yong5 1Department of Otolaryngology, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang 310003, People’s Republic of China; 2Department of Otolaryngology, The First People’s Hospital of Hangzhou City, Hangzhou, Zhejiang 310013, People’s Republic of China; 3Department of Pathology, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang 310003, People’s Republic of China; 4State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang 310003, People’s Republic of China; 5Department of Pathology, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang 310003, People’s Republic of ChinaCorrespondence: Shui-Hong ZhouDepartment of Otolaryngology, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang 310003, People’s Republic of ChinaTel +86-13868060120Email 1190051@zju.edu.cnBackground: Several studies have suggested that laryngopharyngeal reflux disease (LPRD) or gastroesophageal reflux disease (GERD) is an independent risk factor for laryngeal carcinoma. However, it remains unclear whether either condition affects the level of H+/K+-ATPase expression in laryngeal carcinoma.Materials and Methods: Immunohistochemistry, real-time RT-PCR, and Western blotting were used to explore the distributions of proton pump (H+/K+-ATPase) α- and β-subunits in normal laryngeal tissue and laryngeal carcinoma.Results: Messenger RNAs encoding both the α- and β-subunits were found in the normal epiglottic, ventricular fold, vocal fold, and arytenoid mucosae, as well as epiglottic cartilage. The distributions and expression levels of H+/K+-ATPase α-subunits in various laryngeal subregions did not significantly differ in IHC, RT-PCR, or Western blotting. However, Western blotting revealed a significant difference between the expression level of the β-subunit protein in the epiglottic cartilage and the levels in other sites. The expression levels of both subunits were significantly higher in carcinomatous than in paracarcinomatous tissue and normal laryngeal tissue. The mean follow-up duration was 66.2 months (range, 17– 162 months). In all, 4 patients died during follow-up, 4 were lost to follow-up, and 22 were alive and free of disease at the end of follow-up. Two patients developed lung metastases and six developed disease recurrences (at 2, 8, 14, 16, 36, and 41 months). The 3- and 5-year overall survival (OS) rates were 93.0% and 77.0%, respectively. Univariate analyses showed that the 5-year OSs were significantly associated with the T, N, and clinical stages but not with age, alcohol use, pathological differentiation, or the expression levels of the α- or β-subunits (as revealed by IHC, RT-PCR, or Western blotting). However, in multivariate regression analyses, the 5-year OSs were not significantly associated with any clinicopathological factor or the expression levels of either subunit.Conclusion: H+/K+-ATPase is expressed in the normal larynx, including in the epiglottic cartilage and the mucosae of the epiglottis, ventricular fold, and arytenoid vocal fold. The expression levels of the H+/K+-ATPase α- and β-subunits in laryngeal carcinomas were higher than in normal laryngeal tissues.Keywords: proton pump, H+/K+-ATPase, larynx, laryngeal carcinoma, laryngopharyngeal reflux disease