1. Department of Pathology, College of Medicine, King Saud University, Riyadh, Saudi Arabia
2. Department of Medicine, King Fahad Medical City, Riyadh, Saudi Arabia
3. College of Medicine, King Saud University, Riyadh, Saudi Arabia
4. Hematology/Oncology Division, Department of Medicine, College of Medicine, King Saud University, Riyadh, Saudi Arabia.