Genetic Testing for Cancer Risk: Who Needs It, How It Works and What Results Mean
Updated: 2 days ago
Written and medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: November 2026 · How we review
Quick Answer: What is genetic testing for cancer risk?
Genetic testing for cancer risk checks your DNA, usually from a blood or saliva sample, for inherited gene changes that raise your chance of certain cancers, such as changes in the BRCA genes. About 5% to 10% of cancers involve an inherited mutation. A positive result means higher risk, not that you have or will get cancer. [1]
What the research says
BRCA mutations sharply raise lifetime cancer risk. In a prospective study of nearly 10,000 women carrying BRCA1 or BRCA2 mutations, the risk of breast cancer by age 80 was 72% for BRCA1 and 69% for BRCA2, and the risk of ovarian cancer was 44% and 17%. (Kuchenbaecker et al., JAMA, 2017) [2]
Testing everyone with cancer finds more inherited mutations. Among 2,984 patients with solid tumors, 13.3% carried a disease-causing inherited variant, and 6.4% had findings that family-history-based criteria would have missed; 28.2% of those with high-risk variants had their treatment changed. (Samadder et al., JAMA Oncology, 2021) [3]
Key takeaways
The test looks for inherited gene changes that raise cancer risk; it doesn't detect cancer itself. [1]
About 5% to 10% of all cancers involve an inherited mutation. [1]
Genetic counseling is the first step before and after testing. [1]
Results are positive, negative or a variant of uncertain significance (VUS). [1]
Most people get results within two to three weeks. [1]
What is genetic testing for cancer risk?
Genetic tests for cancer risk check your DNA for genetic mutations (changes). If the test finds a mutation, you're at higher risk of developing certain cancers. [1]
Your genes tell your cells how to grow, multiply and eventually die. In cancer, gene mutations turn healthy cells into cancer cells that grow out of control and form tumors that can spread. [1]
Most cancer-causing mutations aren't inherited. But about 5% to 10% of all cancers involve a mutation passed down from a biological parent. Having a cancer-related mutation doesn't mean you will get cancer. It means your risk is higher. [1]
What does genetic testing for cancer risk look for?
Researchers have linked over 400 genes to hereditary cancer.
These tests don't detect cancer itself. They look for specific mutations that sometimes lead to cancer. Researchers have identified over 400 genes linked to hereditary cancer, in three general groups: [1]
Gene group | What it normally does | What a mutation does |
Tumor suppressor genes (such as BRCA and P53) | Put the brakes on cell growth | Lets cancer cells multiply unchecked |
Proto-oncogenes | Help cells grow at a normal pace | Turn into oncogenes that drive cancer growth |
DNA repair genes | Fix mistakes in DNA | Stop repairs, so errors build up |
Sources: [1]
Which cancers can be inherited?
The most common cancers linked to an inherited mutation include: [1]
Breast cancer
Colon cancer
Kidney cancer
Ovarian cancer
Pancreatic cancer
Prostate cancer
Stomach cancer
Thyroid cancer
Uterine (endometrial) cancer
Who should get genetic testing for cancer risk?
A provider may recommend testing if your medical history, or your family's, suggests an inherited mutation. [1]
Your own history
You may need testing if you: [1]
Have had several different types of cancer
Were diagnosed with cancer at a young age
Have a cancer that's uncommon for your age or sex
Have cancer in both organs of a pair, such as both breasts or both kidneys
Have signs of an inherited cancer syndrome, such as neurofibromatosis type 1, which also causes noncancerous tumors called neurofibromas
Belong to a racial or ethnic group known for certain inherited cancer syndromes and have other risk factors
Your family history
You may need testing if: [1]
Several family members have the same type of cancer
Several family members had cancer at a young age
Several relatives on one side of your family have the same cancer
Family members are known to carry an inherited cancer-related mutation
Providers usually consider you at higher risk if a first-degree relative (biological parent, sibling or child) has or had cancer, though more distant relatives can matter too. Talk with a provider or genetic counselor if you're not sure. [1]
How does genetic testing for cancer risk work?
Most people get results within two to three weeks.
Test type | What it looks at |
Single mutation test | One specific spot in one gene, often used when a relative has a known mutation |
Single gene test | The entire DNA sequence of one gene |
Panel test | Mutations in several genes at once |
Sources: [1]
In September 2023, the U.S. Food and Drug Administration (FDA) authorized a test that checks for the most common inherited mutations across 47 genes from one blood sample. [1]
Before the test
Genetic counseling is the first step. A counselor typically discusses whether testing is right for you, which test fits, its pros and cons, what results could mean for you and your family, and how much it costs, including insurance coverage. [1]
During the test
A provider collects a sample of your blood or saliva and sends it to a lab, where technicians look for changes in your genes. [1]
At-home saliva tests exist, but they don't always give a complete and accurate picture of your cancer risk. Your provider must protect your privacy under HIPAA, while companies selling at-home tests don't have to follow the same law. [1]
After the test
Most people get results within two to three weeks. [1]
What do the results mean?
A positive result means higher risk, not a cancer diagnosis.
Result | What it means |
Positive | A mutation linked to a specific inherited cancer was found. Your risk of that cancer is higher |
Negative | No hereditary cancer mutation was found. A "true negative" means your family has a known mutation, but you don't |
Variant of uncertain significance (VUS) | A change was found, but it isn't known to raise cancer risk. It may be harmless or not yet understood |
Sources: [1]
What happens next?
A genetic counselor reviews your results with you. If they're positive, you may discuss: [1]
Extra screenings to catch cancer early and steps to lower your risk
Family planning, including the chance of passing the mutation to a biological child
What your result means for your blood relatives
If your results are negative or a VUS, you may still need regular checkups or follow-up testing. Your provider may contact you if new research links your VUS to a specific cancer. [1]
Benefits and downsides
Genetic testing can: [1]
Relieve anxiety about the unknown
Give you information to lower your cancer risk
Help your provider catch cancer early
Inform decisions about having biological children
Help family members understand their own risk
It can also cause distress, such as anxiety or guilt, and strain family relationships. A genetic counselor can help you process these feelings and talk with relatives about their next steps. [1]
Conclusion
Genetic testing for cancer risk can show whether you've inherited a gene change that raises your chance of certain cancers. Knowing this can help you and your providers plan earlier screening and risk-reducing steps. [1]
Because results can affect your whole family, talk with a genetic counselor before and after testing. [1]
Keep learning: Read our guide to BRCA testing or our Lynch syndrome guide. For more background, see the National Cancer Institute's genetic testing fact sheet.
FAQ
What is genetic testing for cancer risk?
A test of your blood or saliva that looks for inherited gene changes that raise your cancer risk.
Does a positive result mean I have cancer?
No. It means your risk of certain cancers is higher.
How many cancers are inherited?
About 5% to 10% of all cancers involve an inherited mutation.
Who should consider genetic testing for cancer?
People with early or multiple cancers, or several relatives with the same cancer or a known family mutation.
What genes are tested?
Common ones include BRCA and P53, and panel tests can check dozens of genes at once.
What is a variant of uncertain significance?
A gene change whose link to cancer isn't known yet.
How long do genetic test results take?
Most people get results within two to three weeks.
Do I need genetic counseling first?
Yes. Counseling is the first step, and a counselor also explains your results.
Are at-home genetic tests reliable for cancer risk?
They don't always give a complete or accurate picture, so talk to a provider first.
What are the downsides of genetic testing?
It can cause anxiety or guilt and affect family relationships.
Related Reading
Lynch Syndrome: Symptoms, Causes, Inheritance, Diagnosis, and Screening explains a common inherited cause of colon and uterine cancer.
Li-Fraumeni Syndrome: Understanding Genetic Cancer Risks and Management covers the inherited P53 condition.
Breast Cancer: Symptoms, Causes, and Treatment explains one of the cancers most often linked to inherited mutations.
Ovarian Cancer: Symptoms, Causes, and Treatment covers another cancer tied to BRCA mutations.
Pancreatic Cancer: Symptoms, Causes, and Treatment describes a cancer that can run in families.
BRCA Testing and Genetic Testing (DNA Tests) explain related genetic tests.
FISH Test: How Fluorescence In Situ Hybridization Finds Gene Changes explains the glowing-probe lab test that finds gene and chromosome changes.
References
Cleveland Clinic. Genetic Testing for Cancer Risk: Types & Benefits. Cleveland Clinic. Last updated November 7, 2024. https://my.clevelandclinic.org/health/diagnostics/23972-genetic-testing-cancer-risk
Kuchenbaecker KB, Hopper JL, Barnes DR, et al. Risks of Breast, Ovarian, and Contralateral Breast Cancer for BRCA1 and BRCA2 Mutation Carriers. JAMA. 2017;317(23):2402-2416. PMID 28632866. https://doi.org/10.1001/jama.2017.7112
Samadder NJ, Riegert-Johnson D, Boardman L, et al. Comparison of Universal Genetic Testing vs Guideline-Directed Targeted Testing for Patients With Hereditary Cancer Syndrome. JAMA Oncol. 2021;7(2):230-237. PMID 33126242. https://doi.org/10.1001/jamaoncol.2020.6252
Medical disclaimer
This article is for general education only and does not replace advice from a qualified healthcare professional. Talk to your doctor about your own diagnosis and treatment, and seek emergency care right away for severe or sudden symptoms.
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