This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Esophageal disorders, Subject name: Pathology
Predisposing factor for esophageal cancer is all except: 
Select and explain. 
A. Mediastinal fibrosis, B. Diveicula, C. Caustic alkali burn, D. HPV
A: Mediastinal fibrosis
Answer: A: Mediastinal fibrosis 
Explanation: * 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 Zn/Mo/Vit A/ Vit C Achalasia Plummer-Vinson syndrome Frequent consumption of very hot beverages Previous radiation therapy to mediastinum Esophageal diveicula Tylosis et palmaris - ADENOCARCINOMA: Barrett's esophagus