1. Division of Pediatric Hematology/Oncology/Stem Cell Transplant, Columbia University Irving Medical Center, New York, NY
2. Pediatric Hematology and Oncology Unit, Hospital Escuela, Tegucigalpa, Honduras
3. Department of Hematology/Oncology, Hospital Infantil Manuel de Jesús Rivera, Managua, Nicaragua
4. National Unit of Pediatric Oncology, Guatemala City, Guatemala