Bladder cancer
     Bladder cancer refers to any of several types of malignant growths of the urinary bladder. It is a disease in which abnormal cells multiply without control in the bladder. The bladder is a hollow, muscular organ that stores urine; it is located in the pelvis. The most common type of bladder cancer begins in cells lining the inside of the bladder and is called urothelial cell or transitional cell carcinoma (UCC or TCC). Exposure to environmental carcinogens of various types is responsible for the development of most bladder cancers. Tobacco abuse (specifically cigarette smoking) is thought to cause 50% of bladder cancers discovered in male patients and 30% of those found in female patients. Thirty percent of bladder tumors probably result from occupational exposure in the workplace to carcinogens such as benzidine. Approximately 20% of bladder cancers occur in patients without predisposing risk factors. Bladder cancer is not currently believed to be heritable (i.e., does not "run in families" as a consequence of a specific genetic abnormality).