Isolation of circulating tumor cells from patients with metastatic castration-resistant prostate cancer. A. Plot of gating strategy applied on a representative patient sample capturing CD45+/ Epithelial Cell Adhesion Molecule (EpCAM)- WBCs and EpCAM+/CD45- CTCs. B. CTCs and WBCs were sorted onto slide chambers for IF using FACS-based techniques. Cells were stained for DAPI, EpCAM, AR, and Prostate Specific Antigen (PSA). C. The number of events for each of 51 patients who had EpCAM+/CD45- events sorted by FACS-based techniques. The mean (659) and median (80) number of events are indicated. D. Representative CTCs evaluated by IF demonstrating AR staining. The lower panel shows variable AR staining patterns.