Genetic Test Results and What They Mean
If you test positive for a BRCA mutation, you have a greater risk of developing breast and ovarian cancer than women who do not carry the gene mutation. Experts believe undiagnosed women who carry BRCA mutations are up to 7 times more likely to be diagnosed with breast cancer in their lifetime than women who do not.
However, a positive result does not mean you will definitely get a second breast cancer or ovarian cancer. It also does not guarantee others in your family will develop either cancer. Carrying a gene mutation does mean that you have a 50 percent chance of passing that mutation on to each of your children.
If you are the first in your family to have genetic testing, a negative result may mean several things.
- You may not carry a BRCA mutation at all
- If you have a strong family history of breast or ovarian cancer, you might carry a gene mutation that current gene testing can’t identify
- Your counselor may recommend more tests to look for mutations in other genes
Your genetic counselor will help make sense of the results in the context of your personal and family history.
When tests have found no gene mutation in a family with a long history of breast cancer, negative test results need to be interpreted with caution. We know that mutations in the BRCA genes do not explain all hereditary patterns of breast and ovarian cancer. Your counselor may speak with you about other mutations researchers are exploring.
If you test negative for a specific gene mutation that someone else your family has already tested positive for, this is considered a true negative test result.
Though we know of several gene mutations associated with a higher risk of breast cancer, your family may carry an unknown mutation. In this case, your results may come back as inconclusive or uninformative.
A variant of uncertain significance means a change was found in one of your genes, but it wasn’t clear whether that change could cause cancer. You may learn more about the VUS as other people in your family are tested and as research on that mutation continues. As more research is done on the genetic causes of breast cancer, it is possible doctors may find the VUS you have is related to breast cancer. It may also be harmless.
If You Test Positive
- Each of your children has a 50 percent chance of inheriting the mutation, whether male or female
- Any first-, second-, and third-degree relatives, both men and women, are at higher than average risk of developing cancer. They should consider meeting with a genetic counselor to discuss testing
- It is recommended that the most closely related family members, such as parents and children, be tested first, to find out which other family members are most likely to inherit a mutation
If You Test Negative or Uncertain
- Each member of your family should follow an individualized plan of recommended screening.
- A doctor can tell them if they should follow high-risk screening standards.
Talking with family about genetic testing can sometimes be difficult. Your family members may or may not want to know their own results, or may have strong opinions about how you handle yours.