The investigators hypothesize that circulating tumor cells (CTC) will be observed in patients with muscle-invasive or metastatic bladder cancer and that CTC will become undetectable, at least transiently, in a fraction of patients after treatment. To investigate this hypothesis, investigators will assess the levels of CTCs both before and after treatment. The feasibility and potential value of fluorescent in situ hybridization (FISH) in the CTCs will be assessed.