Study to Determine the Feasibility, Evaluability and Variability in Markers of Drug Action in Castration Resistant Prostate Cancer

"Session 1: Biopsies will be taken from the main study lesion and up to 2 metastatic sites at 1 visit or over 3 visits. Both formalin fixed and snap frozen material will be collected. At the session (i.e. once over the potential maximum of 3 visits in a session) a urine sample, blood samples for circulating tumour cells (CTC) and an exploratory blood sample (processed to plasma) will be taken.~Session 2: 7 days +/-3 following the last biopsy taken from Session 1, repeat biopsies from the same tumour sites will be obtained. In cases where this is not possible, it is acceptable to biopsy alternative lesions. As in Session 1 biopsies may be taken at 1 visit or over 3 visits and urine, CTC blood samples and an exploratory blood sample (processed to plasma) will be taken."