1. Faculty of Health Sciences, Thang Long University, Ha Noi, Vietnam
2. Biostatistics Department, Hanoi University of Public Health, Ha Noi, Vietnam
3. Department of Science and Technology, Thanh Hoa Oncology Hospital, Thanh Hoa, Vietnam
4. Molecular and Genetic Epidemiology of Cancer, Vanderbilt University Medical Center, Nashville, TN, USA