Genetic Epidemiology

University of Utah

Colorectal Cancer

According to the American Cancer Society, colorectal cancer is second only to lung cancer in incidence. Fortunately, colorectal cancer is one of the most curable forms of cancer when detected early. Treated promptly, over three-quarters of patients can be cured and are able to return to normal lives. Since the cancer develops over time, it is possible to detect the disease long before symptoms appear.

Polyps are believed to be precursors to cancer. Generally, larger polyps are more likely than others to become malignant. Early detection and treatment of polyps is, therefore, essential. Other risk factors for colon cancer include a history of inflammatory bowel disease, ulcerative colitis, Crohn’s disease, and inflammation of the small intestine. A high fat, low fiber diet also puts an individual at greater.

Signs and symptoms of colorectal cancer include diarrhea, constipation or both alternately; bleeding; narrowing of stool; increased abdominal gas and discomfort. It is also possible to have cancer without any symptoms.

Perhaps the most exciting research news in colorectal cancer in recent years has been the discovery of several genes that lead to a high risk of colon cancer. In December 1993, researchers at Johns Hopkins University and the University of Helsinki announced the discovery of a gene associated with a rare form of familial colon cancer.

Identifying these four rare genes is important, but is only the first step in looking at the genetics of common colon cancer. Now researchers are involved in finding out how common the mutations in the genes are, and how many families are affected. They are also investigating why these mutations cause colon cancer, and how we can identify people who carry the mutated copy of the gene who might be at greater risk for colon cancer. Evidence suggests the mutant forms of these genes are very rare, probably causing less than five percent of all colon cancer cases. This suggests there are other genes for colon cancer that have yet to be discovered. These genes are probably more common than the ones already found.

Our group has been involved in the study of colon cancer for about fifteen years. Since 1980, we have been looking at families with many cases of colon cancer. To date, we have recruited over 150 families.

To learn more about colon cancer, visit the websites listed on the Medically Related Links  page. 

 

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1/4/2000