Tumor Suppressor Genes

The cell cycle is a fundamental process of life, regulated by a balance of positive and negative mechanisms that act at key points during cell growth and differentiation. Proto-oncogenes tend to "push" the cell cycle (in a positively acting manner) by activating various cell cycle pathways within the developing cell. By contrast, tumor suppressor genes normally repress, or "put the brakes on," the activation of the pathways.