There are several types of kidney cancer; by far the most common is renal cell cancer, which will be diagnosed in about 30,800 Americans in 2001. Of particular interest to scientists is the fact that renal cell cancer is one of the few types of cancer in which there are well-documented cases of tumors spontaneously regressing without treatment, although this is extremely unusual and may not affect long-term survival. Bladder cancer will strike some 54,300 people in 2001.

The National Cancer Institute convened a Kidney & Bladder Cancers Progress Review Group (PRG) to identify research priorities and resource needs for progress against these cancers.