1. Department of Pathology, The Fifth Affiliated Hospital, Southern Medical University, Guangzhou, Guangdong 510900, P.R. China
2. Department of Gastroenterology, The Fifth Affiliated Hospital, Southern Medical University, Guangzhou, Guangdong 510900, P.R. China
3. Department of Ears, Nose and Throat, The Third People's Hospital of Shenzhen, Shenzhen, Guangdong 518115, P.R. China