Fan Tang1,2, Chongqi Tu2, Xiawei Wei3. 1. Laboratory of Aging Research and Cancer Drug Target, State Key Laboratory of Biotherapy, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, People's Republic of China. 2. Department of Orthopeadics, West China Hospital, Sichuan University, Chengdu, People's Republic of China. 3. Laboratory of Aging Research and Cancer Drug Target, State Key Laboratory of Biotherapy, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, People's Republic of China. xiaweiwei@scu.edu.en.