Healthcare providers typically do genetic tests (DNA tests) to confirm someone has an inherited (hereditary) cancer caused by genetic mutations. About 5% to 12% of all cancers are caused by genetic mutations. If someone has an inherited cancer, healthcare providers may suggest family members have the same tests to see if they have the same genetic mutations.
In cancer, genetic mutations change how our cells work, particularly how they divide and multiply. The majority of these mutations happen during a person’s lifetime. Sometimes, though, people inherit mutations that put them at increased risk of developing an inherited (hereditary) cancer. Hereditary mutations cause about 5% to 12% of all cancers. Healthcare providers typically do genetic tests (DNA tests) to confirm someone has an inherited (hereditary) cancer.
If genetic tests show you have a hereditary mutation that increases your cancer risk, your healthcare provider may recommend that your family members have the same tests. Genetic testing for cancer may have significant medical, financial and psychological implications. If you’re going to have a genetic test for cancer, you should work with genetic counselors before the tests so you understand all the ways genetic testing for cancer may affect you and your family.
Cleveland Clinic is a non-profit academic medical center. Advertising on our site helps support our mission. We do not endorse non-Cleveland Clinic products or services. Policy
Genetic mutations that lead to cancer change your DNA. Your DNA is responsible for building and maintaining your human structure and is organized into genes. Your genes contain instruction manuals for making proteins. Proteins control millions of actions, including how cells grow and multiply.
Mutations that change the instructions needed to make certain proteins can turn healthy cells into cancerous cells. For example, the TP53 gene has the instruction manual for making a protein called tumor protein 53, or P53. This protein keeps your cells from dividing and growing too quickly or in an uncontrolled way so they become tumors. When your TP53 gene mutates, it loses or changes the instruction manual for making protein 53. Without properly functioning P53 proteins, cells can divide uncontrolled and become cancers.
Cancer may happen when a single gene mutates or several genes that work together mutate. Researchers have identified more than 400 genes associated with cancer development. Many of these genes can cause an increased risk of cancer if they’re inherited. Examples include:
Tumor suppressor genes are among the most common genes linked to cancer. Normally, tumor suppressor genes code for (make) proteins that fix damaged DNA or keep cancerous cells from multiplying.
Tumor suppressor genes put the brakes on cancer cell growth. When these genes mutate, it’s as if they switch from keeping a foot on a vehicle’s brakes to putting a foot down on a vehicle’s gas pedal. When tumor suppressor genes mutate, the cancer cells they’re supposed to keep under control start multiplying uncontrollably to become tumors.
Hereditary mutations can cause a wide variety of cancers. Common forms of these cancers include breast cancer, ovarian, colon, uterine, pancreatic and prostate, stomach, thyroid and kidney cancers. Not all cancers are hereditary. For example, cervical cancer isn’t hereditary.
According to the National Cancer Institute, factors that may indicate you would benefit from having genetic testing for cancer risk include:
In genetic testing for cancer, knowledge may take away some anxiety or fear of the unknown. A person with an inherited cancer may receive specific cancer treatment because genetic testing showed they carry mutated genes linked to that cancer. Additionally, the person and their healthy family members carrying the same hereditary mutation can work with healthcare providers on ways to prevent cancer from happening. A person with inherited cancer can take steps so they don’t pass their hereditary mutation on to their biological children.
Researchers studying the impact of genetic testing on families have found genetic testing can cause psychological distress (such as anxiety and guilt) and affect family relationships.
People with inherited cancerous genes may worry other people — friends, employers, insurance companies — may learn about their situation. People who may have inherited cancerous genes may worry about the possible costs of paying for genetic testing and follow-up tests.
Genetic counseling is the first step in genetic testing. Healthcare providers typically recommend genetic counseling before they do any genetic testing. Trained genetic counselors typically discuss the following topics as part of genetic counseling:
Hereditary genetic cancer tests include:
In genetic testing for cancer, healthcare providers typically collect a sample of your blood or saliva that they send to a laboratory. At the lab, technicians will look for changes in your genes. The technicians send the test results to your healthcare provider. While taking blood takes little time, providers may need days or weeks to complete test analysis.
Genetic tests are a very reliable way to find mutations that may increase your risk of cancer. Again, it’s important to keep in mind that test results can’t state if you’ll definitely develop cancer. These tests show if you carry a mutated gene linked to certain cancers. Genetic tests may not find all mutated genes, or they may find a mutation that may or may not affect the gene in question.
Costs depend on several factors such as your personal and family history and the test ordered. In general, genetic tests may cost a few hundred dollars up to a few thousand dollars. Health insurance often covers some or all costs depending on your personal and family history of cancer. If you’re considering genetic testing for cancer, ask your genetic counselor to outline potential options and costs.
Genetic tests can have several possible results: positive, true negative, uninformative negative or benign.
This test result means you have a genetic mutation that’s linked to a specific inherited cancer. Positive results have different implications depending on why you were tested.
This result means the test didn’t find a mutation associated with an increased risk of cancer. If you have cancer and your genetic test for a certain genetic mutation shows you don’t carry that genetic mutation, it means your cancer isn’t inherited. It also means your family members don’t need to have genetic testing.
If there’s a known mutation in your family, your negative result is a true negative. This means you don’t carry the genetic mutation that increases your family members’ risk of developing cancer. True negative results don’t eliminate all cancer risks. You may still develop cancer, but your risk is the same as any other person in the general population.
If there’s no known mutation in your family but someone in your family has cancer, healthcare providers classify negative results as uninformative negative. You still may be at risk of developing cancer and your provider may recommend you have increased cancer screening,
Medical researchers haven’t identified all genetic mutations that may increase the risk of cancer. That means it’s possible you could have a genetic mutation that hasn’t been associated with an increased risk of cancer or that is just part of normal human variability.
Healthcare providers don’t use VUS when making recommendations, but a person with a VUS result should keep in touch with their provider in case additional research identifies a link between the VUS and a specific inherited cancer.
A benign variant is a common genetic change that doesn’t cause cancer.
If tests show you have an inherited cancer, your healthcare providers will use what they’ve learned to tailor treatment. Genetic counselors will be glad to help you explain your situation to family members.
If your family members were tested, they’ll meet with genetic counselors to review their test results. Counselors will explain test results and options. They’ll do everything they can to help your family feel comfortable with their decisions about genetic testing.
A note from Cleveland Clinic
In a way, genetic testing for cancer may be a mixed blessing. If you have an inherited form of cancer, genetic testing confirms your diagnosis and helps healthcare providers plan treatment. If your family members are worried about their cancer risks, genetic testing may eliminate some of their concerns. But genetic testing for cancer can affect family relationships by creating anxiety, fear and tension. Healthcare providers — particularly genetic counselors — understand how genetic testing for cancer affects family dynamics. Having to cope with cancer already puts pressure on you and your family. You and they’re already dealing with big challenges. Ask your genetic counselor or healthcare provider for help if you think your family is struggling with the idea of genetic testing or test results.
Last reviewed by a Cleveland Clinic medical professional on 08/08/2022.
Learn more about our editorial process.