1. Department of Gastroenterology and Hepatology, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong, P.R.China
2. Department of Gastrointestinal Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong, P.R.China
3. Department of Pathology, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong, P.R.China