[1] Univ Nacl Autonoma Mexico, Fac Estudios Super Zaragoza, Mexico City 04510, DF, Mexico
[2] Univ Nacl Autonoma Mexico, Fac Med, Mexico City 04510, DF, Mexico
[3] Hosp Infantil Mexico Dr Federico Gomez, Clin Epidemiol Unit, Mexico City, DF, Mexico
[4] Inst Politecn Nacl, Ctr Invest & Estudios Avanzados, Dept Pharmacol, Mexico City, DF, Mexico
[5] Hosp Infantil Mexico Dr Federico Gomez, Oncohematol Dept, Mexico City, DF, Mexico
[6] Hosp Pediat Dr Silvestre Frenk Freud, Dept Oncol, Mexico City, DF, Mexico
[7] Inst Mexicano Seguro Social, Coordinat Hlth Res, Av Cuauhtemoc 330, Mexico City 06725, DF, Mexico