Positive for a Deleterious Mutation
or Suspected Deleterious

This information is designed for individuals who have been tested for a hereditary cancer syndrome. It will help you understand the results of your test and is best reviewed with your healthcare provider. Please choose the link below that matches your test result by looking at the patient copy of your test result or contacting the healthcare provider who ordered your test.

The Genetic Test(s) You Received

  • Comprehensive COLARIS®: Full sequence and large rearrangement analysis of the MLH1 and MSH2 genes.
  • Gene-Specific COLARIS®: Analysis of only one of the genes responsible for HNPCC syndrome: MLH1, MSH2, or MSH6.
  • Singe Site COLARIS®: Mutation-specific analysis for individuals with a known MLH1, MSH2, or MSH6 gene mutation in the family.

Your Test Result

  • Positive for a Deleterious Mutation
  • Genetic Variant, Suspected Deleterious

Overview of Your Test Result

Mutations in MLH1, MSH2, and MSH6 cause most cases of hereditary nonpolyposis colorectal cancer (HNPCC), a syndrome that involves various cancers, primarily colon/rectal (colorectal) and endometrial (uterine).

  • You have a mutation or alteration in either the MLH1, MSH2, or MSH6 gene.
  • You have HNPCC syndrome.
  • HNPCC syndrome increases the risk of various cancers, primarily colorectal and endometrial (uterine).
  • The risk of developing these cancers is less than 100%. Not everyone with HNPCC syndrome will develop cancer.

Your Cancer Risks

Having an MLH1, MSH2, or MSH6 mutation increases the risk of certain cancers. If you have already had a cancer diagnosis, you have an increased risk of developing another cancer.

If you have NOT yet had cancer Mutation
Carrier		 General
Population
Colorectal cancer by age 70 Up to 82% 2%
Endometrial (uterine) cancer by age 70 Up to 71% 1.5%
Stomach cancer by age 70 Up to 13% <1%
Ovarian cancer by age 70 Up to 12% 1%
If you HAVE had colorectal cancer Mutation
Carrier		 General
Population
Second colorectal cancer within 10 years 30% 3%
Second colorectal cancer within 15 years 50% 5%

HNPCC mutation carriers may have a slightly elevated risk over the general population of developing cancers of the kidney/urinary tract, brain, biliary tract, small bowel, and pancreas.

Managing Your Risks

Options for reducing cancer risk are available whether or not you have already had a cancer diagnosis. The following are medical management guidelines for individuals with HNPCC syndrome. Discuss these options with the appropriate medical professionals to determine how you will manage your cancer risks.

Increased Surveillance

Site Procedure Age to Begin Repeat
Colon Colonoscopy 20-25 years

(or 5-10 years earlier than the youngest colorectal cancer in the family, whichever comes first)		 1-2 years

Annually after
age 40
Endometrium
(Uterus)/Ovaries		 Gynecologic exam

Transvaginal ultrasound

Endometrial aspiration
(tissue sample)

CA-125		 25-35 years 1-2 years

Screening for other HNPCC-related cancers (stomach, kidney/urinary tract, biliary tract, brain, small bowel, pancreatic) may be considered based on the presence of that cancer in a family member. Please speak to your healthcare provider about this option.

Surgical Management

  • Colectomy (removal of the colon) reduces the risk of colon cancer. The rectum is usually left in place. This is an option for:
    • patients diagnosed with colorectal cancer or advanced adenomas (polyps).
    • unaffected individuals with HNPCC syndrome who are unwilling or unable to undergo regular screening colonoscopies.
  • Preventive removal of the endometrium (uterus) and/or ovaries reduces the risk of endometrial and ovarian cancer. This is an option for:
    • females with HNPCC syndrome who have completed childbearing.
    • females with HNPCC syndrome at the time of other intra-abdominal surgery (i.e. surgery for colorectal cancer).

It’s a Family Affair

HNPCC mutations are passed on in a family. Now that a mutation has been identified in you:

  • Your close blood relatives (parents, children, brothers, and sisters) have a 50% chance of having the same mutation.
  • More distant relatives (cousins, uncles, and aunts) also have a chance of having the mutation that runs in your family.
  • Generally, the mutation is only going to be found on the side of your family (father's or mother's) that has the history of cancer.

Your relatives can be offered Single Site COLARIS® to determine whether or not they have the same mutation.

  • Relatives interested in genetic testing will need to know your specific mutation. It is best to provide your relatives with a copy of your test result which you can obtain from your healthcare provider.
  • Single Site COLARIS® costs much less than a comprehensive test and may be covered by insurance.
  • If your relative is:
    • Positive for the mutation, he/she has the increased cancer risks associated with HNPCC syndrome and can benefit from appropriate medical management.
    • Negative for the mutation, he/she has an average risk of cancer and can follow general population screening guidelines.

Your healthcare provider can assist in determining which of your relatives should consider genetic testing.

If you need a copy of your genetic test result, please contact the healthcare provider who ordered your test.

Next Steps

Please work with your healthcare provider to determine the most appropriate next steps for you.

  • Obtain a copy of your test result.
  • Schedule consultations with appropriate healthcare providers.
  • Create a plan for medical management.
  • Share your genetic test result with your relatives (identify your specific mutation so relatives can have Single Site testing).
  • Re-contact your healthcare provider on a regular basis for new information about HNPCC syndrome.

Additional Resources

Myriad has resources available to help you with your genetic test result.

  • Contact Myriad’s Medical Services Department at 1-800-469-7423 for:
    • Answers to questions about your test result.
    • Information about genetic testing for your relatives.
  • Online tools:

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