1. Division of Pediatric Hematology/Oncology, Pediatric Department, Prince Sultan Military Medical City, Riyadh, Saudi Arabia
2. Department of Pediatric Oncology, National Cancer Institute, Cairo University, Cairo, Egypt
3. Department of Central Military Laboratory and Blood Bank, Prince Sultan Military Medical City, Riyadh, Saudi Arabia
4. Pathology department, King Khalid University Hospital, King Saud University, Riyadh, Saudi Arabia