Colorectal Cancer Genetic Testing
What are the benefits of genetic testing for colorectal cancer genes?
Up to 10% of people diagnosed with colorectal cancer have an that caused their cancer.
- For people with colorectal cancer, genetic test results may affect your cancer treatment options, including allowing you access to newer therapies or to avoid therapies that are less likely to help you.
- Genetic test results may help you and your relatives understand the risk for cancer and take action to stay healthy.
- If you test positive for an , you may have an increased risk for other cancers.
- Your test may allow relatives to learn if they are at increased or average risk for cancer.
- Expert guidelines outline cancer screening and prevention options for people who test positive for a mutation linked to colorectal cancer risk.
Should everyone with colorectal cancer get genetic testing?
Expert guidelines recommend genetic counseling and testing for an for all people diagnosed with colorectal cancer at any age. A genetics expert can help you understand genetic testing, guide you through the process, and explain what the results mean for you and your relatives.
Guidelines for tumor testing followed by genetic testing
Experts recommend tumor testing all colorectal cancers to look for biomarkers known as "" () or microsatellite instability-High () at the time of diagnosis. These two related abnormalities are commonly found in the cancers of people with . For this reason, people with dMMR/MSI-High cancers are recommended to have genetic counseling and testing for .
Read more about this type of testing on our colorectal cancer page.
Colorectal cancer survivors who had testing in the past may benefit from additional genetic counseling and testing
People with colorectal cancer may benefit from additional genetic counseling and expanded genetic testing if they had genetic testing in the past, tested negative, and:
- they had a test that only looked for one or a few genes, or
- they had genetic testing before 2014. Genetic testing has improved, and laboratories can now find gene mutations that may have previously been missed.
Should relatives of people with colorectal cancer get genetic testing?
Genetic counseling and testing is recommended for anyone with the following family history of colorectal cancer:
- one or more 1st-degree relatives who has been diagnosed with colorectal cancer before age 50.
- one or more 1st-degree relatives wo have been diagnosed with colorectal cancer and a second cancer related to (e.g., endometrial, ovarian, stomach, small intestine, urinary tract or other cancers).
- two or more 1st- or 2nd- degree relatives who have been diagnosed with a cancer related to with at least one of the cancers diagnosed before age 50.
- three or more 1st- or 2nd- degree relatives who have been diagnosed with a cancer related to at any age.
Which genes are linked to colorectal cancer?
Mutations in the genes listed below are associated with an increased risk for colorectal cancer. The risks vary by gene. See our section with details for each gene to learn more.
|
Syndrome (if applicable) |
Genes |
Notes |
|
||
|
Familial Adenomatous Polyposis (FAP) and Atypical Familial Adenomatous Polyposis (AFAP) |
|
|
|
MUTYH Associated Polyposis (FMAP) |
|
|
|
Hamartoma Tumor syndrome |
|
|
|
||
|
||
|
Multiple Endocrine Neoplasia 1 syndrome (MEN1) |
MEN1 |
|
|
Other rare genes linked to colorectal cancer |
|
How do I get genetic testing for hereditary colorectal cancer?
Genetic testing is a type of blood or saliva test performed on blood, saliva or tissue. The sample is collected and sent to a genetic testing lab. A doctor or nurse with expertise in genetics or a genetic counselor can help you get genetic testing. You can read more about the process here.