[1] Hannover Med Sch, Hannover, Germany
[2] Univ Hosp Essen, Dept Med Oncol, West German Canc Ctr, Essen, Germany
[3] Univ Hosp, Inst Pathol, Heidelberg, Germany
[4] Natl Ctr Tumor Dis, Heidelberg, Germany
[5] Med Univ Clin, Tubingen, Germany
[6] Univ Krankenhaus Eppendorf, Hamburg, Germany
[7] Charite, Internist Onkol, D-13353 Berlin, Germany
[8] Heidelberg Univ, Natl Ctr Tumor Dis, Heidelberg, Germany
[9] Johannes Gutenberg Univ Mainz, D-55122 Mainz, Germany
[10] Interdisziplinaren Tumorzentrum Mannheim, Mannheim, Germany
[11] Univ Hosp Regensburg, Dept Internal Med, Regensburg, Germany
[12] Tech Univ Munich, Dept Internal Med 2, D-80290 Munich, Germany
[13] Univ Marburg, Dept Gastroenterol, Marburg, Germany
[14] Univ Cologne, Dept Gastroenterol & Hepatol, D-50931 Cologne, Germany
[15] Univ Hosp Freiburg, Dept Med 2, Freiburg, Germany
[16] Klinikum Esslingen, Dept Gastroenterol & Oncol, Esslingen, Germany
[17] Klinikum Magdeburg, Dept Hematol, Magdeburg, Germany
[18] Canc Ctr Reutlingen, Reutlingen, Germany