1. Department of Public Health and Preventive Medicine, School of Medicine, Jinan University, Guangzhou, Guangdong, P.R. China
2. Guangdong Provincial Engineering & Technology Research Center for Tobacco Breeding and Comprehensive Utilization, Key Laboratory of Crop Genetic Improvement of Guangdong Province, Crops Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou, Guangdong, P. R. China
3. Department of Radiation Oncology, Guangdong Provincial People’s Hospital & Guangdong Academy of Medical Sciences, Guangzhou, Guangdong, P. R. China