[1] Univ Illinois, Dept Surg, Div Surg Oncol, Chicago, IL 60680 USA
[2] Ist Clin Humanitas, Digest Endoscopy Unit, Rozzano, Italy
[3] Univ Glasgow, Dept Surg, Glasgow G12 8QQ, Lanark, Scotland
[4] Univ Nacl Autonoma Mexico, Dept Gastroenterol, Inst Nacl Ciencias Med & Nutr, Sch Med, Mexico City 04510, DF, Mexico
[5] Johns Hopkins Univ, Dept Med, Div Gastroenterol, Baltimore, MD USA
[6] Johns Hopkins Univ, Dept Pathol, Baltimore, MD USA
[7] Univ Verona, Dept Pathol & Diagnost, I-37100 Verona, Italy
[8] Univ Verona, Dept Med, Gastroenterol Sect, I-37100 Verona, Italy
[9] Massachusetts Gen Hosp, Dept Med, Div Gastroenterol, Boston, MA 02114 USA