Men with newly diagnosed metastatic prostate cancer have traditionally been treated with hormone therapy alone. New evidence indicates that adding chemotherapy or newer generation hormone therapies can extend the survival of these men. However, these treatments can cause considerable toxicity and there is currently no means to predict which of these treatments would be most effective for a patient’s cancer. We believe that by growing and treating a patient’s own prostate cancer cells in the lab, we will be able to predict which treatment will be most effective to use for that patient in the clinic. We have been able to successfully biopsy and grow a patient’s cancer cells in our lab and measure their response to various treatments. We are proposing to establish proof-of-principle in a group of prostate cancer patients and correlate the treatment response of their cancer cells in the lab with their actual response in the clinic. This may allow us to better tailor treatments for prostate cancer patients in the future.