1. Center of Pediatric Hematology Oncology, Azienda Policlinico OVE, Catania, Italy;
2. Center of Pediatric Hematology Oncology, Azienda Policlinico OVE, Cytogenetic, Cytofluorimetric, Molecular Biology Laboratory, Catania, Italy;
3. Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy