The short answer
Genetic testing for inherited cancer risk looks for gene changes passed down in families that can raise the chance of certain cancers. About 5 to 10 percent of cancers are linked to these inherited changes. Testing can guide screening, prevention, and sometimes treatment, but it has emotional and practical trade-offs and works best alongside genetic counseling.
About 5 to 10 percent of cancers are caused by inherited gene changes.
Testing looks for specific inherited changes that raise cancer risk, usually from a blood or saliva sample.
It is most useful for people with a personal or family history that suggests an inherited pattern.
Results can be positive, negative, or a variant of uncertain significance.
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The full explanation.
The simple version
Most cancers are not inherited. But about 5 to 10 percent of all cancers are linked to gene changes that are passed down in families. These inherited changes can raise the chance of certain cancers.
Genetic testing for inherited cancer risk looks for those specific changes. It usually uses a sample of blood or saliva, because an inherited change is present in every cell of the body.
This kind of testing can help people understand their risk and plan screening or prevention — but it is not right or needed for everyone.
What the test is (and isn't)
Genetic testing for inherited risk looks for changes you were born with, sometimes called germline changes, mutations, or pathogenic variants.
This is different from testing a tumor to guide treatment. Tumor testing looks at changes that happened during a person's life. It can sometimes pick up inherited changes, but it does not replace testing for inherited cancer risk.
Inherited-risk testing asks: were you born with a change that raises your cancer risk?
Who might consider testing
Cancer can seem to run in a family for many reasons, including shared habits like tobacco use, not just genes. But certain patterns make an inherited change more likely. A doctor or genetic counselor may suggest testing when there is:
- A relative with a known inherited gene change that raises cancer risk
- Cancer diagnosed at a young age (for example, colon cancer before 50)
- Several relatives with the same type of cancer
- Certain cancer combinations in a family, such as breast and ovarian, or colon and endometrial
- Rare cancers, such as breast cancer in a man
- Cancer in both of a pair of organs, such as both breasts
Some diagnoses — like ovarian, pancreatic, or triple-negative breast cancer — also lead to a testing recommendation. When possible, testing often starts with a family member who has had cancer.
Testing is most informative for people with a history that hints at an inherited pattern.
How testing is done
A genetic counselor or doctor usually reviews your personal and family history first. If testing makes sense, a small sample — most often blood or saliva — is sent to a lab. Results typically come back in about 2 to 3 weeks.
Often the lab runs a panel test that checks several genes at once. If a specific change is already known in the family, the test may look just for that change.
What the results mean
Results generally fall into three groups:
- Positive. A harmful change was found. This can raise the risk of certain cancers and may guide earlier or more frequent screening, prevention steps, or treatment choices. It does not mean cancer is certain — some people with a harmful change never develop cancer.
- Negative. No harmful change was found. This is most reassuring when a specific family change is known and you did not inherit it (a "true negative"). If your family's cause is unknown, a negative result does not rule out risk from your history.
- Variant of uncertain significance (VUS). A change was found, but there is not yet enough data to know if it matters. Most are later reclassified as harmless. Until then, decisions are based on your history.
A result is a piece of the picture, not a verdict — its meaning depends on your family history too.
Benefits and downsides
Testing can offer real benefits no matter the result:
- Peace of mind if you did not inherit a known family change
- A chance to plan screening or prevention if a harmful change is found
- Information that helps relatives understand their own risk
- Guidance for treatment if you already have cancer
There are also downsides to weigh:
- Emotional stress from learning about increased risk, for yourself or family
- Uncertainty from a VUS result
- Cost, if not fully covered
- Privacy considerations
There is no single right choice — it depends on your history, your feelings, and your goals.
Privacy and protections
Genetic results usually become part of your medical record. A federal law called GINA prohibits health insurers and most employers from using genetic information to discriminate. It does not cover life, disability, or long-term care insurance, and does not apply to the military. A genetic counselor can walk you through what is and is not protected.
A word about at-home tests
Some companies sell direct-to-consumer genetic tests. These often do not check for every important change and are not always meant for medical decisions. For example, the only FDA-approved at-home test for inherited cancer risk checks for just three BRCA changes and misses most harmful BRCA variants. Genetic counseling helps make sure the right test is done and the results are understood.
Words to know
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Common questions
▸What does genetic testing for cancer risk actually look for?
It looks for specific inherited changes, sometimes called mutations or pathogenic variants, in genes that can raise the risk of certain cancers. This is different from testing a tumor to guide treatment. Inherited-risk testing uses a sample of blood or saliva because an inherited change is present in every cell of the body.
▸Who should consider this kind of testing?
It is generally considered for people whose personal or family history suggests an inherited pattern — such as cancer at a young age, several relatives with the same cancer, certain cancer combinations in a family, or a known gene change in the family. Some cancer diagnoses also lead to a testing recommendation. A genetic counselor can help decide if it makes sense for you.
▸What do the possible results mean?
A positive result means a harmful change was found, which can raise cancer risk but does not mean cancer is certain. A negative result may be reassuring, especially if a family change is known, but does not remove all risk. A variant of uncertain significance means there is not yet enough information to know if the change matters.
▸Will my insurance cover genetic testing?
Health insurance often covers genetic counseling and testing when it is considered medically necessary. Coverage varies, so it helps to check with your provider and insurer beforehand. Some programs offer testing at reduced or no cost for people who qualify.
▸Can my results affect my family?
Yes. Because relatives share genes, a result can carry information about your blood relatives, not just you. This is one reason genetic counseling is helpful, and why testing is often started with a family member who has had cancer when possible.
▸Could my results be used against me?
A federal law called GINA prohibits health insurers and most employers from discriminating based on genetic information. It does not cover life, disability, or long-term care insurance, and does not apply to the military. A genetic counselor can explain these protections and their limits.
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