Authors' Affiliations: 1Brigham and Women's Hospital, and 2Massachusetts General Hospital, Boston, Massachusetts, 3Pfizer, Inc., 4Memorial Sloan-Kettering Cancer Center, New York, New York; 5University of Wisconsin, Madison, Wisconsin; 6CCS Associates, Inc., Mountain View, California; 7University of Newcastle upon Tyne, Newcastle upon Tyne, United Kingdom; 8Harris Methodist Hospital, Ft. Worth, Fort Worth, Texas; 9Regional Gastroenterology Associates of Lancaster, Lancaster, Pennsylvania; 10Sir Charles Gairdner Hospital, Perth, Western Australia, Australia; 11The Royal Melbourne Hospital, Melbourne, Victoria, Australia; 12Nashville Medical Research Institute, Nashville, Tennessee; 13Atlanta Gastroenterology Associates, Atlanta, Georgia; 14St. Paul's Hospital, University of Saskatchewon, Saskatoon, Saskatchewon; Canada, 15National Cancer Institute, Bethesda, Maryland; and 16M. D. Anderson Cancer Center, Houston, Texas (At 2009-04-01)