What Is Genetic Testing for Inherited Cancer Risk?
Genetic testing can help us understand if your cancer diagnosis or your family history of cancer is due to something hereditary, meaning something that can be passed on in the family.
This test doesn't tell a person if they currently have cancer or if they will or will not get cancer in the future. However, it may help us understand your risk for cancer over your lifetime.
How Does Genetic Testing Work?
- Genetic testing looks at your genes.
- Genes are like different instructions that tell your body how to function.
- Some genes protect you from cancer; if these cancer-fighting genes do not work correctly, you may be at a higher risk of getting cancer.
- Genetic testing can tell us if these genes have changes that cause them to work differently than expected.
What Is the Purpose of Genetic Testing?
- To understand why you developed cancer
- If you have cancer, to inform your treatment plan, e.g., surgery or chemotherapy
- To give information to your family members that can help them understand their risk for cancer or other conditions
- To prevent or lower the chance of a future cancer diagnosis or other condition
How Is the Testing Done?
- During a genetics visit, you will meet with a genetic counselor or health care provider.
- They will ask about your medical and family history to determine the best genetic test for you.
- Genetic testing usually involves a blood, saliva or cheek swab, but may sometimes require a skin sample.
What Types of Genetic Testing Are Available at City of Hope?
There are two main ways to get testing at City of Hope; both are comprehensive and appropriate for our patient care.
City of Hope's Center for Precision Medicine is now enrolling people in a general research consent study, which enables research seeking better ways to prevent, diagnose and treat cancer.
Our genetic specialists can discuss your options, personalizing your care to your family and situation if you want to pursue testing outside the research study.
For more information about genetic counseling services, click here.
A positive test result means testing has identified a pathogenic change (sometimes called a variant or genetic mutation) linked with increased cancer risk. Knowing about this risk can help health care providers guide patient care, from screening and surgeries to medications.
These mutations also impact family members, such as children, siblings, parents, aunts, uncles, cousins, and grandparents. Typically, parents pass down these changes to their children, so it is possible that others in the family are at risk and don't know it. It may be helpful for them to get genetic testing.
A negative test result means testing hasn't identified a genetic change associated with cancer risk, meaning we could not find a hereditary cause for a family history of cancer. But it doesn't mean there's no chance of cancer.
There are a few reasons why we could get a negative result:
- We may not know about the gene causing these cancers and, as a result, cannot test for it yet.
- The laboratory may be unable to detect all of the changes in the genes tested due to technical limitations.
- A genetic change could run in the family the person tested did not inherit.
- The cancers might not be hereditary but sporadic or caused by shared exposures and the environment.
Even with a negative result, there could still be a genetic change in the family that increases cancer risk. It might benefit other people in the family to do genetic testing.
An uncertain test result means that testing has identified a change in the gene that we currently don't have enough information to call positive or negative. Everyone has some changes in their genes that make them unique. Most of the time, these changes do not cause any health problems.
An uncertain result doesn't require action. However, once we learn more about it, we may reclassify it as a positive or negative result that can impact your health care. If our genetics team follows you, we will reach out if we are informed your uncertain result has been reclassified in a way that would affect your cancer risks or management. We also encourage our patients to contact genetics every few years to see if we can offer new recommendations or testing.