The Gene Factor:
Gene p53

Known since 1979, the p53 gene is located on chromosome 17 and acts to regulate the cell cycle. It is rather unreactive in cells where DNA is undamaged. When there is DNA damage, however, the p53 gene suspends the cell cycle until the damage can be repaired. If there is a mutation in p53, the cell cycle continues unrestrained and reproduces the damaged DNA, leading to uncontrolled cell proliferation and cancer tumors. Cancer results because, as the cell with damaged DNA divides, the damaged DNA is replicated and each daughter cell's cycle is also unrestrained.

The gene is actually made up of 393 amino acids. Its name is derived from "p" for protein and 53 because of its molecular mass of 53,000 atomic mass units. Nearly half of all human cancers are related to a mutation in the gene, making it the most frequently encountered mutation in all of cancer. Among the cancers involved are breast, colon, lung, liver, prostate, bladder, and skin. Among the carcinogens that affect p53 are ultraviolet radiation and cigarette smoke.

The p53 gene was originally discovered by Arnold Levine, David Lane and William Old. It was first thought to be an oncogene, but 10 years later a team lead by Bert Vogelstein and Ray White, then studying colon cancer, showed p53 to be a tumor suppressor.

For more information, at other Web sites...

How Some Cancer Cells Cheat Death — article about the discovery of a protein that inhibits gene p53 in killing cancerous cells, from BBC News, 27 April 2004.

p53, Molecule of the Year — from the Howard Hughes Medical Institute.

Professor Sir David Lane — from the University of Dundee.

Dr. Bert Vogelstein — from Johns Hopkins University.