1. Department of Gastroenterology, The First Affiliated Hospital of University of South China, Hengyang 421001, Hunan Province, P.R. China
2. Cancer Research Institute, Hunan Province Key Laboratory of Tumor Cellular and Molecular Pathology, University of South China, Hengyang 421001, Hunan Province, P.R. China
3. Department of Otorhinolaryngology, The First Affiliated Hospital of University of South China, Hengyang 421001, Hunan Province, P.R. China