The most common known causes for cancer of the ureter are environmental. And it stands to reason because the urine is constantly in contact with the lining of the upper urinary tract. So any toxin that you’re exposed to that gets filtered into the urine is going to coat the lining of the urinary tract, sometimes for decades. The best known example of this is tobacco exposure. There’s at least 70 known carcinogens or cancer causing chemicals in cigarette smoke. Everyone knows about lung cancer resulting from cigarette smoke. Not many know about the urinary tract threats. Because of these toxins are in contact with the upper urinary tract, tobacco exposure can eventually lead to DNA changes in the lining of the upper urinary tract that, many years later, leads to the development of ureteral cancer. Other risk factors include use of an anti-inflammatory medication called phenacetin. It hasn’t been around since the 1980s, because it was banned once this association was known. In Balkan countries, such as Greece, Bulgaria, Romania, there’s a inflammatory condition of the kidney called Balkan nephropathy. And this inflammation can ultimately be associated with cancers of the ureter. In a very small percentage of cases, there’s a genetic component, a rare syndrome called Lynch syndrome, which causes cancers to form in the colon and uterus, is also occasionally associated with cancer formation in the ureter.