The integration of molecular genetics into cancer management.

Many of the phenotypes of cancer cells and tumors can now be traced to specific mutations in the genomes of these cells. These mutations may activate oncogenes, providing mitogenic stimulus to these cells. Alternatively, they may inactivate tumor-suppressor genes, relieving growth-inhibiting constraints placed on these cells. These genetic lesions together provide many of the explanations for the deregulated growth of tumor cells.