1. College of Medicine, Alfaisal University, P.O. Box 50927, Riyadh 11533, Saudi Arabia
2. Department of General Surgery, Faculty of Medicine, Alexandria University, Alexandria 21526, Egypt
3. Department of Surgical Oncology, King Faisal Specialist Hospital and Research Center (KFSH&RC), P.O. Box 3354, Riyadh 11211, Saudi Arabia
4. Department of Pathology and Laboratory Medicine, King Faisal Specialist Hospital and Research Center (KFSH&RC), P.O. Box 3354, Riyadh 11211, Saudi Arabia