1. Department of Pathology, Medical College, Jinan University, Guangzhou, Guangdong 510632, P.R. China
2. Chinese Academy of Sciences Key Laboratory of Regenerative Biology, Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, Guangdong 510530, P.R. China