[1] St Jude Childrens Res Hosp, Memphis, TN 38105 USA
[2] Unidad Nacl Oncol Pediat, Guatemala City, Guatemala
[3] Lab Patol Dra Elizabeth Orellana, Guatemala City, Guatemala
[4] Clin Radioterapia Asuncion, Guatemala City, Guatemala
[5] Univ Illinois, Coll Med, Peoria, IL USA
[6] Univ Colorado, Sch Med, Childrens Hosp Colorado, Aurora, CO USA
[7] Univ Colorado, Anschutz Med Ctr, Pediat Hematol Oncol SCT, Aurora, IL USA
[8] Univ Colorado, Anschutz Med Ctr, Hemophilia & Thrombosis Ctr, Aurora, CO USA
[9] Fdn IRCCS San Gerardo dei Tintori, Tettamanti Ctr, Monza, Italy
[10] Fdn IRCCS San Gerardo Tintori, Pediat, Monza, Italy
[11] Fdn IRCCS Ist Nazl Tumori, Milan, Italy
[12] Hosp St Damien, Port Au Prince, Haiti
[13] Hosp Nacl Ninos Benjamin Bloom, San Salvador, El Salvador