1. Department of Surgery and Urology for Children and Adolescents, Medical University of Gdansk, 80-210 Gdansk, Poland
2. Department of Pediatrics, Hematology and Oncology, Medical University of Gdansk, 80-210 Gdansk, Poland
3. Department of Radiology, Medical University of Gdansk, 80-210 Gdansk, Poland
4. Department of Pathology and Neuropathology, Medical University of Gdansk, 80-210 Gdansk, Poland
5. Department of Pediatric Oncology and Hematology, Medical University of Bialystok, 15-089 Bialystok, Poland
6. Department of Pediatric Oncology, Pomeranian Medical University, 71-210 Szczecin, Poland
7. Department and Clinic of Haematology, Blood Neoplasms, and Bone Marrow Transplantation, Medical University of Wroclaw, 50-425 Wroclaw, Poland
8. Department of Pediatric Oncology, Hematology and Chemotherapy, Medical University of Silesia, 40-752 Katowice, Poland
9. Department of Pediatric Oncology Hematology and Transplantology, Poznan University of Medical Sciences, 60-572 Poznan, Poland