1. Department of Human anatomy
2. Histology and Embryology
3. College of Medicine
4. Qingdao University
5. Qingdao
6. Department of Urology
7. Xinqiao Hospital
8. the Third Military Medical University
9. Chongqing 400037
10. China
11. State Key Laboratory of Molecular Developmental Biology
12. Institute of Genetics and Developmental Biology
13. Chinese Academy of Sciences
14. Beijing 100190