<prompt> Predisposing factor for esophageal cancer is all except:Mediastinal fibrosisDiveiculaCaustic alkali burnHPV  <response>: External beam irradiation but not mediastinal fibrosis is risk factor for esophageal cancer. HPV DNA is found frequently in esophageal squmaous cell carcinoma in high incidence regions. OTHER RISK FACTORS PREDISPOSING TO CARCINOMA OF ESOPHAGUS: - SQUAMOUS CELL CARCINOMA: Alcohol tobacco use Intake of nitrosamines Caustic esophageal injury Deficiency of ZnMoVit A Vit C Achalasia Plummer-Vinson syndrome Frequent consumption of very hot beverages Previous radiation therapy to mediastinum Esophageal diveicula Tylosis et palmaris - ADENOCARCINOMA: Barretts esophagus 