This information explains the multi-gene panel test for hereditary colorectal cancer (colon and rectal cancer) and polyps. It also explains how your results may affect you and your family.
In this resource, the word “family” means family members related to you by blood. They are not related to you through marriage or adoption.
This multi-gene panel test is done to check your DNA for gene mutations linked to hereditary colorectal cancer. Normally, these genes help prevent cancer. A mutation in these genes causes them to stop working like they should. This increases your risk for certain types of cancers.
For more information, read Hereditary Colon Cancer and Polyposis.
What is a multi-gene panel test?
We can test for mutations one gene at a time or multiple genes at the same time. A multi-gene panel test is when we test multiple genes at once using the same saliva or blood sample. By testing multiple genes at once, it may be possible to find a hereditary cause of cancer more quickly.
What genes will be tested on my multi-gene panel?
Click on the table to the right to enlarge it and see what genes are tested on this multi-gene panel test. The column on the left shows which cancers you may have an increased risk for if you have a mutation. The other columns show the genes we’ll test. It’s important to know that the risk isn’t the same for all cancers listed. This means the risk for some cancers increases more than the risk for other cancers.
Your genetic counselor will review your genetic test results with you. They’ll talk with you about whether you have a mutation and what cancer(s) it’s linked to. As we learn more about these mutations, we may learn that they increase the risk for other types of cancers.
What happens if I have a mutation?
If you have a mutation, your genetic counselor will review your results and your personal and family history of cancer and give you cancer screening recommendations.
They may recommend you start having cancer screenings at a younger age, have them more often than most people, or get specialized screenings to help find cancer as early as possible.
Some examples of these cancer screenings include:
- Getting colonoscopies starting at an earlier age and more often than most people.
- Getting an upper endoscopy (a procedure that lets your doctor see inside your stomach and small intestine).
- Having a urinalysis (a test to look for blood in your urine).
Depending on which gene mutation(s) you have, your genetic counselor may also talk with you about having surgery to try to keep cancer from developing, such as:
- Surgery to remove your uterus to prevent endometrial cancer.
- Surgery to remove your ovaries to prevent ovarian cancer.
If you’re having surgery for colon cancer or polyps, your genetic counselor may recommend you have extra colon tissue removed to prevent colon cancer.
If you decide to have surgery, talk with your genetic counselor about the right time to have it. Surgery to remove the uterus or ovaries affects fertility (ability to have biological children). If you plan to have biological children, your genetic counselor can talk with you about your options.
What happens if I don’t have a mutation?
If you don’t have a mutation or if we find a variant of uncertain significance (a change in your gene that isn’t called a mutation or normal because we don’t know enough about it yet), your genetic counselor will review your personal and family history. They’ll talk with you about the general cancer screening guidelines you should follow.
What does a gene mutation mean for my blood relatives?
Most of the mutations you’ll be tested for are passed down in a dominant pattern. This means you only need to inherit the mutation from one parent to have an increased risk for cancer. If you have a mutation in one of these genes, your biological parents, siblings, and children each have a 50% chance of having the same mutation in that gene. This means there’s an equal chance they will or won’t have the mutation. Your distant family members may also be at risk for having the same mutation.
The MUTYH, NTHL1, and MSH3 genes are passed down in a recessive pattern. This means you need to inherit these mutations from both parents to have an increased risk for cancer. People who inherit just one recessive gene mutation from one parent typically don’t have a higher risk of getting cancer.