Molecular genetics and biochemical mechanisms in bladder cancer. Oncogenes, tumor suppressor genes, and growth factors.

Transitional-cell carcinoma of the bladder is believed to arise through a series of genetic changes affecting cell growth and proliferation. Two basic types of such genes have been described: protooncogenes and tumor suppressor genes. The former have not been studied extensively in bladder cancer, although there is evidence that c-erb B-2/neu is overexpressed. Loss of specific chromosomal regions, which is common in bladder tumors, may inactivate tumor suppressor genes, of which p53 has received the most attention. Work also has been done on epidermal growth factor and its receptor, yielding evidence that malignant and normal urothelium have different sensitivities to its action. Although several advances must be made before genetic changes come to the clinical forefront, the information now being gained with such speed holds considerable promise for diagnosis and treatment.