1. Department of Biomorphology, University G. D'Annunzio, 66100 Chieti, Italy
2. Laboratory of Clinical Biochemistry, Istituto Superiore di Sanità, 00161 Rome, Italy
3. Laboratory of Cell Biology, Istituto Superiore di Sanità, 00161 Rome, Italy
4. Laboratory of Servizio Qualità Sicurezza Animale, Istituto Superiore di Sanità, 00161 Rome, Italy
5. Department of Hematology, University of Florence, 50139 Florence, Italy
6. Department of Pediatric Oncology, Children's Hospital, Dana Farber Cancer Institute, Harvard Medical School and Howard Hughes Medical Institute, Boston, MA 02115