Genetic testing looks for an inherited change (mutation) in a gene that is known to increase the risk for specific types of cancer. It is usually done on a blood or saliva sample.
Only about 5-10% of all cancers are linked to an inherited gene mutation. Genetic testing is offered if your personal and/or family history of cancer meets specific criteria.
The first test in a family is usually offered to someone who has had cancer. This is called an index test. Storage of a blood sample may be a good idea for a person with uncertain health, if they might be the best index for genetic testing in a family. Please contact your MD/NP or the Hereditary Cancer Program to discuss this option.
Most index genetic testing is currently done using a panel of hereditary cancer genes. Your genetic counsellor will review which genes are being tested and the possible results.
If a hereditary cancer gene mutation is found, then a specific carrier test is available for family members. A carrier test looks only for the specific gene mutation that has been confirmed in your relative.
Hereditary cancer genetic testing is usually offered to adults. It is available to children if the results will change their medical care.
Genetic counselling is an important part of a decision to have genetic testing. For more information on genetic counselling, expand the "What is genetic counselling?" section above.