1. Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas2Parkland Health and Hospital System, Dallas, Texas3Department of Clinical Sciences, University of Texas Southwestern Medical Center, Dallas4Harold C. Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas
2. Division of Gastroenterology, Veterans Affairs San Diego Health Care System, San Diego, California6Department of Internal Medicine, Moores Cancer Center, University of California, San Diego, La Jolla
3. Department of Clinical Sciences, University of Texas Southwestern Medical Center, Dallas4Harold C. Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas
4. Parkland Health and Hospital System, Dallas, Texas
5. Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas
6. Department of Clinical Sciences, University of Texas Southwestern Medical Center, Dallas