1. Department of Urology and Bio-X Program, Stanford University, Stanford, CA 94305, USA.
2. Veterans Affairs Palo Alto Health Care System, Palo Alto, CA 94304, USA.
3. Institute for Stem Cell Biology and Regenerative Medicine, Stanford University, Stanford, CA 94305, USA.
4. Department of Pathology, Stanford University, Stanford, CA 94305, USA.
5. Molecular Imaging Program at Stanford and Departments of Radiology and Bioengineering, Stanford University, Stanford, CA 94305, USA.