1. Department of Epidemiology and Health Statistics & Henan Key Laboratory of Tumor Epidemiology, College of Public Health Zhengzhou University Zhengzhou China
2. Laboratory of Molecular Biology Henan Luoyang Orthopedic Hospital & Henan Provincial Orthopedic Institute Zhengzhou China
3. Henan Institute of Medical and Pharmaceutical Sciences Zhengzhou University Zhengzhou China
4. Department of Pathology The University of Iowa Iowa City IA USA