1. Department of Oncology, Chinese PLA General Hospital, Beijing, P.R. China
2. Department of Gastroenterology, The Second Medical Center of the Chinese PLA General Hospital, Beijing, P.R. China
3. The Second School of Clinical Medicine, Southern Medical University, Guangzhou, Guangdong province, P.R. China
4. Department of Thoracic Surgery, The First Affiliated Hospital of Kunming Medical University. No. 295, Xichang Road, Wuhua District, Kunming, Yunnan Province 650032, P.R. China
5. Department of Oncology, Chinese PLA General Hospital. No.8, Dongdajie, Fengtai District, Beijing 100071, P.R. China