1. Department of Gastroenterology and Hepatology, Chinese PLA General Hospital, Beijing 100853, China
2. Medical College of NanKai University, Tianjin 300071, China
3. State Key Laboratory of Molecular Oncology, Cancer Institute and Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, P.R.China
4. Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University, Baltimore, Maryland 21231, USA
5. The Hillman Cancer Center, University of Pittsburgh Cancer Institute, Pittsburgh, PA 15213, USA