1. Department of Medical Microbiology, School of Basic Medical Sciences, Shandong University, Jinan, Shandong 250012, P.R. China
2. China National Tobacco Quality Supervision and Test Center, Zhengzhou, Henan 450001, P.R. China
3. Cancer Therapy and Research Center, Shandong Provincial Hospital, Shandong University, Jinan, Shandong 250021, P.R. China
4. Department of Clinical Laboratory, Qilu Hospital of Shandong University, Qingdao, Shandong 266035, P.R. China