[1] Univ Minnesota, Dept Pediat, Div Bone Marrow Transplantat, Minneapolis, MN 55455 USA
[2] Univ Minnesota, Dept Therapeut Radiol Radiat Oncol, Minneapolis, MN 55455 USA
[3] Univ Minnesota, Ctr Canc, Minneapolis, MN 55455 USA
[4] Amgen Inc, Thousand Oaks, CA 91320 USA