[1] Univ Perugia, IBit Fdn, Sect Haematol & Immunol, I-06100 Perugia, Italy
[2] Columbia Univ, Inst Canc Genet, Herbert Irving Comprehens Canc Ctr, New York, NY USA
[3] Columbia Univ, Dept Pathol, Herbert Irving Comprehens Canc Ctr, New York, NY USA
[4] Univ Basel Hosp, Dept Res, CH-4031 Basel, Switzerland
[5] Univ Roma La Sapienza, Dept Cellular Biotechnol & Haematol, Rome, Italy
[6] MLL Munich Leukemia Lab, Munich, Germany
[7] Univ Wurzburg, Inst Pathol, D-8700 Wurzburg, Germany
[8] Univ Foggia, Inst Haematol, Foggia, Italy