1. Department of Pathology, Faculty of Medicine, Chulalongkorn University, Pathumwan, Thailand
2. King Chulalongkorn Memorial Hospital and Thai Red Cross Society, Pathumwan, Thailand
3. Department of Obstetrics and Gynecology, Faculty of Medicine, ChulalongkornUniversity, Pathumwan, Thailand
4. Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada