[1] Natl Inst Paediat, Dept Surg Oncol, Mexico City, DF, Mexico
[2] ABC Canc Ctr, Mexico City, DF, Mexico
[3] Anahuac Univ, Naucalpan De Juarez, Mexico
[4] Hosp Nino Poblano, Educ, Puebla, Mexico
[5] Mexican Board Paediat Surg, Mexico City, DF, Mexico
[6] Natl Inst Paediat, Stem Cell Transplantat & Cellular Therapy, Mexico City, DF, Mexico
[7] Natl Inst Paediat, Dept Epidemiol Res, Mexico City, DF, Mexico