1. 1Department of Epidemiology, College of Public Health, Zhengzhou University, 100 Science Avenue, Zhengzhou 450001, China
2. 2Henan Key Laboratory of Tumor Epidemiology, Zhengzhou University, 40 Daxue Road, Zhengzhou 450052, China
3. 3Department of Biological Sciences, The University of Texas at El Paso, 500 West University Avenue, El Paso, TX 79968, USA