Correspondence to: Prof. CHEN Bao-an, Department of Hematology, Zhongda Hospital and Faculty of Oncology, Medical School, Southeast University, Nanjing, Jiangsu 210009, China (Tel: 86-25-83272006. Fax: 86-25-83272011. Email: cba8888@hotmail.com); Prof. WANG Xue-mei, State Key Laboratory of Bioelectronics (Chien-Shiung Wu Laboratory), Southeast University, Nanjing, Jiangsu 210096, China (Tel and Fax: 86-25-83792177. Email: xuewang@seu.edu.cn)