1. Departments of Medicine and Biological Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, USA
2. Veterans Affairs Greater Los Angeles Healthcare System & University of California at Los Angeles, CA, USA
3. Department of Gastroenterology, Nanlou Division, The PLA General Hospital, Beijing, China
4. Robert H. Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
5. Department of Medicine, University of Illinois-Chicago, Chicago, IL, USA
6. Division of Gastroenterology and Hepatology, Department of Medicine, Stanford University School of Medicine, Stanford, CA, USA
7. Center for Health and the Environment, University of California, Davis, CA, USA