1. Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, MD, USA
2. Division of Cancer Epidemiology and Prevention, Cancer Center and M. Sklodowska‐Curie Institute of Oncology, Warsaw, Poland
3. Division of Gastrointestinal Pathology, Armed Forces Institute of Pathology, Washington, DC, USA
4. Division of Histopathology, Cancer Center and M. Sklodowska‐Curie Institute of Oncology, Warsaw, Poland
5. Division of Upper Digestive Tract Cancer, Cancer Center and M. Sklodowska‐Curie Institute of Oncology, Warsaw, Poland
6. Department of Gastroenterology, Medical Center for Postgraduate Education, Cancer Center and M. Sklodowska‐Curie Institute of Oncology, Warsaw, Poland
7. Westat, Inc., Rockville, MD, USA
8. International Epidemiology Institute, Rockville, MD, USA