1. Department of Pediatrics, Hematology and Oncology, Medical University of Gdansk, Gdansk, Poland
2. Children’s Hospital of Michigan, Detroit, MI, USA
3. Department of Pathology and Neuropathology, Medical University of Gdansk, Gdansk, Poland
4. Department of Pediatrics, Hematology and Oncology, University Clinical Centre, Gdansk, Poland
5. Department of Pathomorphology, Medical University of Gdansk, Gdansk, Poland
6. The English Division Pediatric Oncology Scientific Circle, Medical University of Gdansk, Gdansk, Poland
7. Department of Pediatrics, Gastroenterology, Hepatology and Nutrition, Medical University of Gdansk, Gdansk, Poland