1. Department of Medicine, Section of Gastroenterology and Hepatology, Virginia Tech Carilion School of Medicine and Research Institute, Roanoke, Virginia, USA
2. Department of Pathology, Carilion Clinic and Dominion Pathology Associates, Roanoke, Virginia, USA
3. Department of General Surgery, Section of Surgical Oncology, Wake Forest University School of Medicine, Winston-Salem, North Carolina, USA