Fast Five Quiz: How Much Do You Know About Colorectal Cancer?

Tomislav Dragovich, MD, PhD


October 07, 2016

Although much about colorectal cancer genetics remains unknown, current research indicates that genetic factors have the greatest correlation to colorectal cancer. Hereditary mutation of the APC gene is the cause of familial adenomatous polyposis (FAP), in which affected individuals carry an almost 100% risk of developing colon cancer by age 40 years.

Hereditary nonpolyposis colon cancer syndrome (HNPCC), or Lynch syndrome, poses about a 40% lifetime risk of developing colorectal cancer; individuals with this syndrome are also at increased risk for urothelial cancer, endometrial cancer, and other, less common cancers. Lynch syndrome is characterized by deficient mismatch repair (dMMR) due to inherited mutation in one of the mismatch repair genes, such as hMLH1, hMSH2, hMSH6, hPMS1, hPMS2, and possibly other undiscovered genes. HNPCC is a cause of about 6% of all colon cancers.

Dietary factors are the subject of intense and ongoing investigations. Epidemiologic studies have linked increased risk for colorectal cancer with a diet high in red meat and animal fat, low-fiber diets, and low overall intake of fruits and vegetables.

Factors associated with lower risk include folate intake, calcium intake, and estrogen replacement therapy. However, most of these studies were retrospective epidemiologic studies and have yet to be validated in prospective, placebo-controlled, interventional trials. Obesity and lifestyle choices such as cigarette smoking, alcohol consumption, and sedentary habits have also been associated with increased risk for colorectal cancer.

For more on the etiology of colon cancer, read here.


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