Transitional cell carcinoma (TCC) is the most common type of bladder cancer in dogs. Most dogs with TCC initially show signs such as straining to urinate, increased frequency of urination, or blood in the urine. As the tumor grows, it obstructs the flow of urine, which can become life-threatening. TCC can also spread to nearby lymph nodes, lungs, and bones. In most cases, TCC of the bladder cannot be cured.