The bladder is an organ that collects urine before it is removed from the body by urination, being an important part of the urinary tract. The urinary tract is made up of kidneys, ureters, and urethra. The bladder, like other parts of the urinary tract, is lined with a layer of cells called urothelium. This cell layer is separated from the muscles of the bladder wall, called it\’s own muscular, of a thin, fibrous band called lamina propria.

Bladder cancer develops when healthy cells in the bladder mucosa, most commonly urothelial cells, change and develop uncontrollably, forming a mass called the tumor.