Molecular biology of proto-oncogenes in genitourinary cancers.

The application of molecular biology to oncology has allowed the recognition of altered genes in cancer cells. The DNA sequences most commonly altered belong to the family of proto-oncogenes, which are homologous to the cancer-causing genes of RNA tumor viruses. In the normal cell, proto-oncogenes apparently have important functions in regulation of growth and differentiation. When altered by mutation, deletion, translocation or amplification in cancer cells, proto-oncogenes may disrupt fundamental cellular processes. Such aberrant functioning by abnormal proto-oncogenes may play crucial and even causative roles in cancer development. Altered proto-oncogenes have been identified in cancers of the human urogenital tract. Studies on the expression of proto-oncogenes in genitourinary cells will increase understanding of basic biological properties of these cells, and may yield information relevant to staging, diagnosis, risk factors, and markers of pathologic classification.