1. Department of Pathology, Professor Witold Orlowski Public Clinical Hospital, Medical Center for Postgraduate Education, Czerniakowska 231, 00-416 Warsaw, Poland
2. Department of General & Experimental Pathology, Medical University of Warsaw, Krakowskie Przedmiescie 26/28, 00-927 Warsaw, Poland
3. Department of Gastroenterology and Hepatology, Medical Center for Postgraduate Education, Roentgena 5, 02-781 Warsaw, Poland
4. Department of Surgery, Professor Witold Orlowski Public Clinical Hospital, Medical Center for Postgraduate Education, Czerniakowska 231, 00-416 Warsaw, Poland