Bladder cancer accounts for approximately 90% of cancers of the urinary tract. The bladder is an organ located in the pelvic cavity that stores and discharges urine. Urine is produced by the kidneys, carried to the bladder by the ureters, and discharged from the bladder through the urethra. Bladder cancer usually originates in the bladder lining, which consists of a mucous layer of surface cells that expand and deflate smooth muscle and a fibrous layer. Tumors are categorized as low-stage or high-stage. A number of factors are believed to increase the risk of developing bladder cancer; cigarette smoking is by far the biggest single risk factor. Symptoms of bladder cancer can include blood in the urine, painful urination and increased frequency of urination. Most bladder cancers are diagnosed through the use of cystoscopy, a procedure in which the urologist views the inside of the bladder using a fiberoptic scope. Once a tumor has been found, it will usually be removed with a procedure called a Transurethral Resection of Bladder Tumor or TURBT.