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.

The measurement of circulating tumor cells is pursued in several cancers including breast and prostate cancer. The number of cells measured in these cancers has been shown to be prognostic. There is little information on the presence or importance of circulating tumor cells in bladder cancer. This trial is designed to determine if patients with advanced bladder cancer have circulating tumor cells and if these circulating cells are affected by treatment of the cancer.

Inclusion Criteria:

• Pathological diagnosis of transitional cell carcinoma of the urothelium of at least T2-4, Nx, Mx stage. Mixed histologies will be allowed (e.g. squamous differentiation) as long as a transitional cell component is present.
• Clinical plans for surgery (with or without chemotherapy), radiation therapy, or chemotherapy.
• Participants must not have any condition which in the investigator's opinion may compromise the feasibility of completing the study.
• Subject must be 18 years of age or older
• Subject must be willing to have up to 4 peripheral blood samples obtained over a 6 month period of study.
• Prior therapies for bladder cancer will be allowed if patient currently has muscle-invasive or metastatic bladder cancer despite the previous treatments.
• Predicted life expectancy of > 12 weeks.

Exclusion Criteria:

• Subjects who are unwilling or unable to comply with the study guidelines as determined by the principal investigator.

Patients with muscle-invasive or metastatic bladder cancer with plans for cancer treatment.