Oncogenes and cancer

Oncogenes - mutated proto-oncognes that abnormally infuence the rate of growth of cells. Researchers believe oncogenes play a role in the development of cancer by altering cellular growth through one or more mechanisms. Oncogenes may accelerate cell division, block APOPTOSIS (planned cell death), or in other ways allow cells to grow beyond the boundaries of the body’s normal controls. MOLECULARLY TARGETED THERAPIES and MONOCLONAL ANTIBODIES (MABS) show significant promise for altering oncogenes to reduce their role in the development of cancer.

Proto-oncogenes are the normal genes which contain the genetic code that tells cells which proteins, and how much of them, to produce to direct the cell’s own growth. These proteins, called signaling proteins, act as messengers within the cell. When proto-oncogenes mutate, their genetic instructions become garbled. The protein production they regulate changes. The cell may produce too many proteins that instruct it to grow, or not enough proteins that instruct it to stop growing. In either circumstance the cell’s growth becomes excessive.

Oncogenes do not alone cause cancer, though researchers remain uncertain about the extent to which they influence the development of cancer. Other genetic and environmental factors come into play, affecting various aspects of cellular growth. Mutations may occur in the genes that regulate DNA repair, for example, allowing damaged cells to replicate. Researchers believe it is the convergence of factors, the emergence of oncogenes among them that permits cancer to develop.

See also CELL STRUCTURE AND FUNCTION; TUMOR SUPPRESSOR GENES.

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