Questions and Answers about the Conversion MethodAnd Testing for Hereditary Colon Cancer Risk

1. What is colorectal cancer?

The colon and rectum are parts of the body’s digestive system, which removes nutrients from food and stores waste until it passes out of the body.  Together, the colon and rectum form a long, muscular tube called the large intestine (also called the large bowel).  The colon is the first 6 feet of the large intestine and the rectum is the last 8 to 10 inches.

 Cancer that begins in the colon is called colon cancer, and cancer that begins in the rectum is called rectal cancer.  Cancers affecting either of these organs may also be called colorectal cancer.

2. What are HNPCC and FAP?

 HNPCC or Hereditary Non-Polyposis Colon Cancer and FAP or Familial Adenomatous Polyposis are inherited cancer syndromes that account for approximately five percent of all colon cancers.  In HNPCC, families typically have at least three members with a history of colorectal cancer, and patients commonly develop cancers at an early age.  Patients with FAP also have a strong family history of colon cancer and develop multiple polyps at a young age, some of which ultimately turn malignant if preventive measures are not taken.  In both HNPCC and FAP, the major genes (basic units of heredity) that cause the diseases are known.

3. Is there a test to identify the genes that are associated with these diseases?

 The genes associated with HNPCC and FAP were identified nearly a decade ago, but early tests were only able to detect genetic mutations a portion of the time.  A new method called Conversion has been developed that identifies nearly 100 percent of mutations in genes known to cause colon cancer susceptibility.  People who have these genetic mutations are considered to be at increased risk of developing colon cancer. 

4. Who should be tested?

 Testing using the Conversion method may be useful to people with a family history of HNPCC or FAP even if they have had colon cancer.  The test can provide valuable information related to the medical care of families with a history of these inherited cancer syndromes.  

5. Who should not be tested?

 Currently, the Conversion method is not useful to those who do not have a family history of HNPCC or FAP.

6. When will the test be available?

 The Conversion method will be available this summer through Johns Hopkins in conjunction with genetic counseling and risk assessment.  A special Johns Hopkins hotline has been established for those seeking additional information on the Conversion method for HNPCC and FAP at 410-955-4041.

7. What is involved in testing?

 Individuals with a family history of HNPCC or FAP provide a blood sample that is analyzed, using Conversion, for specific mutations related to their inherited syndrome.  Before an individual makes a decision about testing, he or she must meet with a specially trained genetic counselor.  The counselor will explain the advantages and disadvantages of testing, interpret gene test results, and provide information and recommendations for appropriate screening and diagnostic tests. 

8. What does a positive test result mean?

 If a person tests positive for mutations associated with an inherited cancer syndrome, it means he/she carries that particular mutation within their genetic makeup and, as a result, has an increased risk (genetic counselors will explain the risk) of developing colorectal cancer in his/her lifetime.  The test only determines a person’s inherited susceptibility to colorectal cancer, it does not test for the presence of polyps or cancer. 

9. What follow-up care is recommended for those with a positive test result using the Conversion method?

  Regular screening to ensure early detection if a cancer should develop or to prevent the development of cancer is of the utmost importance for individuals receiving positive test results.  The individual’s genetic counselor and physician will make specific recommendations for routine screening and examination.  In general, these include:

·        Routine colonoscopy beginning at an early age.

·        Tests and/or screening for other cancers associated with a particular inherited syndrome.

·        Relatives of individuals testing positive for genetic mutations also should consider genetic

  unseling and risk assessment.

10. What does a negative test result using the Conversion method mean?

  A negative test result means that the individual tested does not carry the mutation(s) in genes associated with his or her family’s hereditary colon cancer syndrome.  These individuals may still carry other genetic mutations not yet identifiable.  These issues, and others, are evaluated through genetic counseling so that appropriate screening recommendations can be made.

11. Should individuals who received another type of genetic test for HNPCC or FAP consider retesting with the Conversion method?

  Yes, those families who received earlier genetic tests for HNPCC and FAP and received inconclusive results should discuss the benefits of retesting using the new technology with a genetic counselor.  Prior tests were successful in detecting mutations 50 percent of the time in HNPCC and 75 percent in FAP.  The new Conversion method is more technologically advanced, and can detect mutations nearly 100 percent of the time.  Those who received prior tests and had positive results (a mutation was identified) would not benefit from retesting.

12. How much does the Conversion method cost, and do insurance carriers pay for it?

 The cost of the Conversion method ranges between $200 – $300 above the cost of conventional testing based on the number of genes being analyzed.  Some insurance carriers cover genetic counseling and testing, while others do not.  Those interested in counseling and testing should refer to their individual insurance policies regarding coverage.

13. Is discrimination a risk for those seeking genetic testing?

 The purpose of genetic testing and counseling is to help families predisposed to the development of potentially life-threatening diseases.   However, with any predictive genetic test comes the potential for discrimination by insurance carriers, employers, and others.  Many who seek testing have concerns about how this information will affect them personally as well as other family members.  These issues are carefully explained and discussed by genetic counselors prior to testing. National legislation that protects the privacy of people undergoing genetic testing and prohibits discrimination is currently being developed.  President Clinton signed an executive order on February 9, 2000 banning genetic discrimination by federal employers.

14. Could the Conversion method be used to detect other disease-related mutations?

 Yes, the researchers who developed the Conversion method believe this technology could be used to assess genetic risk for a variety of hereditary diseases, including other types of cancer, cardiovascular disease, and certain neurological disorders.  However, the initial use of the test will be only for colon cancer. 

15. If a person does not have a family history of colon cancer, does that mean he/she is not at risk for the disease?

  No, colorectal cancer occurs most commonly in those with no known inherited    predisposition.  Risk increases with age, so regular screening for those with no family history is recommended after age 50.  Diet, exercise, and other lifestyle factors also impact on risk.  Currently, genetic testing of the general population is not considered useful or cost-effective.   However, information obtained in the study of those with inherited colon cancer syndromes is not only helpful in the medical management of these syndromes but provides insight into the causes of colon cancers that occur sporadically among the general public.

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