[1] Boldrini Childrens Hosp, Dept Pathol, Campinas, SP, Brazil
[2] Univ Estadual Campinas, Dept Surg, Boldrini Childrens Hosp, UNICAMP, Campinas, SP, Brazil
[3] Univ Estadual Campinas, Sch Med Sci, UNICAMP, Campinas, SP, Brazil
[4] Boldrini Childrens Hosp, Dept Oncol, Campinas, SP, Brazil
[5] Dept Pediat Oncol, Campinas, SP, Brazil
[6] Univ Estadual Campinas, FCM, CIPED, Campinas, SP, Brazil
[7] St Jude Childrens Res Hosp, Dept Oncol, Memphis, TN 38105 USA
[8] St Jude Childrens Res Hosp, Int Outreach Program, Memphis, TN 38105 USA