1. Department of Pediatric Hematology/Oncology, Prince Sultan Military Medical City, Riyadh, Saudi Arabia
2. Department of Central Military Laboratory and Blood Bank, Prince Sultan Military Medical City, Riyadh, Saudi Arabia
3. Pediatric Oncology Department, National Cancer Institute, Cairo University, Cairo, Egypt
4. Basic Science Department, College of Medicine, Princess Nourah Bint Abdulrahman University, Riyadh, Saudi Arabia