Tumor - If the DNA cannot be repaired, the p53 protein...

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Tumor-Suppressor Genes Damaged or mutated DNA may result in uncontrolled cell growth. Proteins produced by some tumor-suppressor genes stop the cell cycle when DNA becomes damaged. If the DNA cannot be repaired, these proteins cause the cell to kill itself (called apoptosis ). For example, a peeling sunburn is due to apoptosis. The DNA has become too badly damaged to be repaired, so the cells kill themselves. This prevents cancer from developing from the mutations. A tumor-suppressor gene called p53 stops the cell cycle when damage has occurred to DNA and it stimulates repair enzymes to repair the DNA. It produces a protein that combines with the cyclin-kinase complex and inactivates it, thus preventing the cell from dividing.
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Unformatted text preview: If the DNA cannot be repaired, the p53 protein stimulates apoptosis. When tumor-suppressor genes don't function properly, they may not be able to prevent abnormal cell division in mutated cells and the result could be cancer. The most frequent cause of new cancer is a mutation in the p53 gene. It is involved in an estimated 60% of all cancers including cancers of the breast, lung, liver, skin, prostate, bladder, cervix, and colon. Breast cancer prognosis is associated with a tumor suppressor gene called p27. Many cancers are the result of tumor suppressor genes that have become "turned off" so that they do not function properly. Therapies are being developed to turn these genes back on....
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This note was uploaded on 12/15/2011 for the course BIO BSC1010 taught by Professor Gwenhauner during the Fall '10 term at Broward College.

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