National Cancer Institute
Science Behind the News Understanding Cancer
A drawing of a cell showing how tumor suppressor gene proteins help to prevent cancer.

Tumor Suppressor Genes Act Like a Brake Pedal

Tumor suppressor genes are a family of normal genes that instruct cells to produce proteins that restrain cell growth and division. Since tumor suppressor genes code for proteins that slow down cell growth and division, the loss of such proteins allows a cell to grow and divide in an uncontrolled fashion. Tumor suppressor genes are like the brake pedal of an automobile. The loss of a tumor suppressor gene function is like having a brake pedal that does not function properly, thereby allowing the cell to grow and divide continually.

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