How to analyze genetic test results?

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Genetic testing can have several possible outcomes: positive, negative, variant of unknown significance, or benign polymorphism. These results are described below.

A "positive test result" means that a specific genetic change (or mutation) has been found that is associated with an inherited cancer syndrome. A positive result can:

-Confirm the diagnosis of an inherited cancer syndrome, indicate an increased risk of developing certain types of cancer in the future, and provide important information that can help other family members make decisions about their own health care. In addition, people who test positive, indicating that they are at increased risk of developing cancer in the future, may be able to take steps to reduce their risk or to diagnose cancer early.

- In patients who have already been diagnosed with cancer, a positive result for a mutation associated with certain hereditary cancer syndromes may influence treatment options. For example, some changes interfere with the body's ability to repair DNA damage. If someone with one of these conditions receives a standard dose of radiation or chemotherapy to treat the cancer, they can experience more severe, potentially fatal, side effects. Knowing the genetic alteration, before starting treatment, allows doctors to modify the treatment, thus reducing the severity of side effects. The surgical option may also change with the indication of prophylactic or risk-reducing surgeries.

A "negative test result" means that no specific change was found for which the test was designed. This result is most useful when working with a family in which there is a specific genetic alteration that causes the disease. In this case, a negative result shows that the tested family member did not inherit the mutation that is present in their family and that this person, therefore, does not have the familial cancer syndrome, therefore does not have an increased genetic risk of developing cancer or not carries a mutation that increases the risk of cancer

If genetic tests show a change that was not previously associated with cancer in other people, the test result may report "variant of unknown significance". This result can be interpreted as ambiguous (uncertain), which means that the information does not help in decision making for health care. If the test reveals a genetic mutation common in the general population among people without cancer, the mutation is called a polymorphism. All commonly have genetic variations (polymorphisms) that are not associated with any increased risk for developing the disease.