How do Tumor Suppressor Genes Work?
A. In cancer cells there are oncogenes and tumor suppressor genes. The oncogenes are considered the acceleratorthey promote the growth of the tumor when they become altered. So overexpression of oncogenes pushes cell proliferation. The tumor suppressor genes are like the brakes in the cellthey prevent cells from growing too rapidly or even growing at all. Q. Do you find tumor suppressor genes in all cells? A. Yes. Quite a few have been discovered, including p53, retinoblastoma, and inhibitors of cyclin-dependent kinases. Cyclin-dependent kinases are important for progression through the cell cycle. If this cycle stops, then the cell can’t grow. The cyclin-dependent kinase inhibitors put brakes on progression through the cell cycle. Q. Is cancer always associated with altered activity of tumor suppressor genes? A. Yes, all cancers have some tumor suppressor dysfunctions, and p53 is most commonly affected. Also, deregulation of the pathway in which the retinoblastoma tumor suppressor pro
