 - CRPC with metastatic disease with at least one site of metastatic disease must be amenable to needle biopsy. Soft tissue biopsy sites include: lymph node or visceral metastases. Bone sites include lumbar vertebrae, pelvic bones and long bones. Excluded sites are thoracic, cervical vertebrae, skull and rib lesions. Biopsy site will be selected with guidance of interventional radiologist determining best site to optimize balance of obtaining useful tissue for analysis and minimizing risk. 