1. Department of Surgical Oncology for Children and Youth; Institute of Mother and Child; Warsaw Poland
2. Department of Obstetrics and Gynecology; Institute of Mother and Child; Warsaw Poland
3. Department of Pediatric Hematology; Oncology and Transplant; Medical University of Lublin; Lublin Poland
4. Department and Clinic of Pediatric Oncology; Hematology and Bone Marrow Transplantation; Wroclaw Medical University; Wroclaw Poland
5. Department of Pediatric Hematology and Oncology Collegium Medicum; Nicolaus Copernicus University; Bydgoszcz Poland
6. Department of Pediatric Hematology and Oncology; Medical University of Gdansk; Gdansk Poland
7. Department of Paediatric Hematology and Oncology; Medical University of Lodz; Lodz Poland
8. Pediatric Oncology; Dana-Farber/Boston Children's Cancer and Blood Disorders Center; Harvard Medical School; Boston Massachusetts