1. Department of HematologyPediatrics Hospital, Siglo XXI National Medical Center, IMSS, Mexico City, Mexico
2. Department of PediatricsGabriel Mancera Hospital, IMSS, Mexico City, Mexico
3. National Institute of Cancer Ssa, Mexico City, Mexico
4. Department of HematologyBernardo Sepúlveda Hospital, Siglo XXI National Medical Center, IMSS, Mexico City, Mexico
5. Department of HematologyMedial Specialties Hospital, La Raza National Medical Center, IMSS, Mexico City, Mexico
6. Department of Pediatric HematologyGeneral Hospital, La Raza National Medical Center, IMSS, Mexico City, Mexico
7. Oncological Research UnitOncology Hospital, Siglo XXI National Medical Center Av. Cuauhtemoc 330, Col. Doctores, IMSS, Mexico, D.F. 06720, Mexico City, Mexico