[1] Inst Jules Bordet, Dept Med, B-1000 Brussels, Belgium
[2] CHU Lille, Serv Malad Sang, F-59037 Lille, France
[3] Weston Pk Hosp, Canc Res Ctr, Sheffield, S Yorkshire, England
[4] Penn State Univ, Milton S Hershey Med Ctr, Div Hematol Oncol, Hershey, PA 17033 USA
[5] Amgen Inc, Thousand Oaks, CA 91320 USA