ABSTRACT
Urothelial carcinoma (UC), known also as transitional cell carcinoma (TCC), can affect any portion of the urothelium, which includes the renal pelvis, the ureter, the bladder, and the prostatic and penile urethra. The normal uroepithelium is composed of several different cell subtypes and is usually three to seven layers thick. Basal cells attach to the lamina propria basement membrane; a few intermediate cell layers separate the basal cells from apical cells known as umbrella cells. Umbrella cells project into the lumen of the urinary tract and serve a key role in providing a barrier against solutes and waste products in the urine.
