[1] Univ Torino, San Luigi Gonzaga Univ Hosp, Dept Clin & Biol Sci, Reg Gonzole 10, I-10043 Turin, Italy
[2] Boston Childrens Hosp, Div Hematol Oncol, Karp RB 8215,300 Longwood Ave, Boston, MA 02115 USA
[3] Dana Farber Canc Inst, Dept Pediat Oncol, Boston, MA USA
[4] Harvard Med Sch, Harvard Stem Cell Inst, Broad Inst, Dept Pediat, Boston, MA USA