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Gene mutations that cause cancer are something scientists have been studying since genetics became a popular science. Being able to identify these mutations will help to prevent cancer because if a patient knows that they are at an increased risk, they can take the steps necessary to prevent themselves from developing the cancer their genes may have set them up for. There are two primary gene types that scientists have discovered play a role in cancer.
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The majority of oncogenes are mutations of proto-oncogenes, certain normal genes. Proto-oncogenes are referred to as the “good” genes necessary for the normal control of the type of cell and its division. When this gene becomes mutated into and oncogene, it is then considered “bad” that can become permanently activated or turned on when it should not be. When this occurs, cancer can occur due to the cell growing out of control.
Inherited proto-oncogene mutations may cause a few cancer syndromes. For example, an inherited RET gene mutation can cause multiple endocrine neoplasia type 2. Hereditary gastrointestinal stromal tumors can be caused by an inherited KIT gene mutation. Hereditary papillary renal cancer can be caused by inherited MET gene mutations.
Most oncogene-related mutations that result in cancer are not inherited, but acquired. Gene duplication, mutation, or chromosome rearrangements generally activate oncogenes. For example, if chromosome arrangement can result in a BCR-ABL gene formation which can cause chronic myeloid leukemia. Most gastrointestinal stromal tumors are caused by KIT gene activations through acquired mutations.
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Tumor Suppressor Genes
Tumor suppressor genes can be gene mutations that cause cancer when they are not functioning properly. These genes are normal and they repair DNA mistakes, slow down the division of cells, and tell cells when they need to die. When these genes are not working correctly, cancer can result due to cells growing out of control. Several different tumor suppressor genes have been discovered, including BRCA1, APC, p53, BRCA2, and RB1. These genes result in cancer when they become inactivated, or turned off, which makes them different from oncogenes which cause cancer when they are activated, or turned on.
Inherited tumor suppressor gene mutations result in certain cancers running in families. For example, familial adenomatous polyposis is caused by a defective APC gene. Most mutation associated with these genes are not inherited, but acquired. For example, more than 50 percent of cancers in humans have a p53 gene abnormality present. Acquired mutations of this gene is present in a variety of cancers, such as colorectal cancer, lung cancer, and breast cancer.
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Montelone, B.A., Ph.D. (1998). Mutations, Mutagens, and DNA Repair. Retrieved on September 16, 2010 from Kansas State University: http://www-personal.ksu.edu/~bethmont/mutdes.html
Medical News Today. (2007). More Gene Mutations Drive Cancer Than Previously Thought. Retrieved on September 16, 2010 from Medical News Today: http://www.medicalnewstoday.com/articles/64804.php