1. Department of Pathology, Third Affiliated Hospital, Guangzhou Medical University, Guangzhou 510150, China
2. Department of Pathology, First Affiliated Hospital, Changsha 410005, China
3. Department of Pathology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
4. Department of Pathology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
5. Key Laboratory of Major Obstetric Diseases of Guangdong Province, The Third Affiliated Hospital, Guangzhou Medical University, Guangzhou 510150, China