Pepsin and laryngeal and hypopharyngeal carcinomas

Laryngeal and hypopharyngeal carcinomas are common malignant tumors of the head and neck, which are both exhibiting increasing incidences. Laryngopharyngeal reflux is the retrograde flow of gastric contents into the larynx, oropharynx, and/or nasopharynx. There remains controversy regarding whether laryngopharyngeal reflux is a risk factor for laryngeal and hypopharyngeal cancers. The refluxing substances mainly include hydrochloric acid, pepsin, and occasionally bile acids and bile salts, as well as bacteria that colonize the gastrointestinal tract. Loss of epithelium in the mucous membrane of the larynx and hypopharynx is presumably caused by pepsin. Here, we review the relationships between laryngopharyngeal reflux and both laryngeal and hypopharyngeal carcinomas, as well as the significance of pepsin, methods of clinical detection, and the mechanism of carcinogenesis.