After performing tumor biopsies and processing the biopsies, the researchers will perform comprehensive molecular analysis using established methods for RNA and DNA sequencing. The researchers will also collect blood samples (for circulating tumor DNA, plasma, and serum) and circulating tumor cells from participating patients. Residual paraffin-embedded blocks, frozen tissue, and blood products (serum, plasma, and circulating cells) will be stored in a repository for future testing of candidate predictive markers identified during microarray analysis. Whenever possible, the researchers will utilize a CLIA-certified laboratory to identify genetic mutations within mCRPC tumors to provide genetic information that can be returned to patient to potentially inform treatment decisions.