Better Screening		Medical Genetics
Questions & Answers		Research Update

Questions & Answers
I’ve heard about a new genetic test that can help predict the risk of colon cancer among persons of Ashkenazi Jewish descent. Can you give me details about the test and why it’s applicable only to Ashkenazi Jews?
Researchers recently discovered a mutation in the APC (adenomatous polyposis coli) gene, known as APC 11307K, that is associated with a family history of colorectal cancer. The only group of persons that seem to carry this mutation are Jews of Ashkenazi (Eastern and Central European) descent. In theory, this may be due to a genetic change that occurred spontaneously centuries ago and has been passed down through generations of Ashkenazi Jews. The mutation is believed to be present in 6 percent of the Ashkenazi Jewish population.

This gene test looks for this single gene mutation, APC 11307K, associated with colorectal cancer in the Ashkenazi Jewish population. The test is performed on a small sample of blood.

What does a “positive” gene test mean?
It means that the person has an increased risk (20 to 30 percent) of developing colorectal cancer or polyps in his or her lifetime. The average risk among persons who do not have this mutation and who do not have a family history of colon cancer is 6 percent. This test does not, however, detect the presence of cancer or polyps.

What does a “negative” test result mean?
It means that the person does not carry this specific mutation found in Ashkenazi Jews. However, this person may still have a mutation in another gene that causes hereditary colon cancer. Risk may be evaluated through genetic counseling where family history, lifestyle and other factors may be discussed.

What should you do if you receive a positive gene test result?
Early diagnosis is critical for timely detection and prevention of colon cancer. At this time, experts have made the following recommendations for people who test positive for the APC 11307K mutation: have routine colonoscopy every 2 years beginning at age 35, or 5 to 10 years before the earliest age at which colon cancer or polyps occurred in the family; patients with a personal history of colon cancer or polyps should have routine colonoscopy every 2 years; and, relatives of persons testing positive for this mutation should consider genetic counseling and testing. These recommendations may be subject to change based on specific family history information. The Cleveland Clinic is one of only a few centers in the country performing this genetic test.

If you have any additional questions or wish to arrange for an appointment, call Medical Genetics at 216/445-5686 or 800/998-4785.