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Posted By pcfadmin On March 23, 2011 @ 6:04 pm In | No Comments
People who have “family medical histories” of colorectal cancer are more likely to develop the disease. That means more than one first-degree relative (parent, sibling or child) has had colorectal cancer or colorectal polyps. Risk increases if relatives were diagnosed at a young age. In some families, parents can pass along changes in certain genes that can lead to colorectal cancer in their children. Scientists have identified several “genetic mutations” for colorectal cancer, and there might be others that have yet to be found.
In addition to these hereditary colon cancers, there are other genetic problems that are not cancers or precancerous conditions and also increase colorectal cancer risk. These include Peutz-Jeghers syndrome (which can cause dark freckles on the lips and mouth), Juvenile Polyposis and Cowden syndrome. People with a family history of colorectal polyps or colorectal cancer should talk with their health care professionals about genetic counseling and testing.
Because scientists have identified the genes responsible for hereditary colon cancer syndromes, we now have genetic tests that can determine whether or not a person has inherited the mutation.
Genetic testing of people without colorectal cancer, but who have a family history of the disease, typically involves taking a small sample of blood. The testers take DNA from white blood cells in the sample and look for the mutations.
When health care professionals suspect colorectal cancer is the result of HNPCC, a sample of the tumor is examined to screen for genetic instability. If the genes are unstable, then a blood sample can be used to test for a mutation in one of the several genes that has been linked to HNPCC. This test is not always definitive. In more than 30 percent of families with HNPCC, a mutation can’t be detected by genetic testing.
When considering genetic testing for colorectal cancer, it is important to speak with a genetic counselor. Genetic counselors can help you understand what having a genetic test may mean and help you make a decision about whether testing is right for you.
Article printed from Prevent Cancer Foundation: http://preventcancer.org
URL to article: http://preventcancer.org/prevention/preventable-cancers/colorectal-cancer/family-history/
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