[1] Mem Sloan Kettering Canc Ctr, Dept Med, Serv Gastroenterol & Nutr, New York, NY 10021 USA
[2] Harvard Univ, Sch Med, Boston, MA 02115 USA
[3] Boston Univ, Sch Med, Boston, MA 02118 USA
[4] Univ Texas, MD Anderson Canc Ctr, Houston, TX 77030 USA
[5] Amer Canc Soc, Atlanta, GA 30329 USA
[6] Oregon Hlth & Sci Univ, Portland, OR 97201 USA
[7] Univ Utah, Huntsman Canc Inst, Salt Lake City, UT USA
[8] Kaiser Permanente Med Ctr, Walnut Creek, CA USA
[9] Univ Minnesota, Minneapolis, MN USA
[10] Univ Colorado, Denver, CO 80202 USA
[11] Univ Vermont, Burlington, VT USA
[12] Univ Texas, SW Med Ctr, Dallas, TX 75230 USA
[13] Creighton Univ, Omaha, NE 68178 USA
[14] Eastern Virginia Med Sch, Norfolk, VA 23501 USA
[15] Indiana Univ, Sch Med, Indianapolis, IN 46204 USA