Marion is a 45-year-old, Ashkenazi Jewish woman who was diagnosed with breast cancer a year ago and is currently undergoing treatment with chemotherapy. Marion has two daughters, ages 11 and 13.

Although she is eager to know whether there's a genetic basis for her cancer, she's worried about getting an inconclusive test result. This would increase her anxiety about her daughters' risk without providing her with any way to protect them (given their ages).

Marion's mother is alive and cancer-free at the age of 68. Her father was diagnosed with prostate cancer at age 71 and is currently alive and doing well. His sister, Marion's paternal aunt, was diagnosed with breast cancer at age 67 and died two years later of metastatic breast cancer. Marion has a number of aunts, uncles, and cousins who are all in good health and cancer-free.

Marion's Decision

After discussing her options with her doctor and a genetic counselor, Marion decides to pursue testing via multisite analysis because her personal history and ethnicity make one of the three BRCA alterations detected in Ashkenazi Jewish women the most likely genetic culprit for her cancer.

An additional benefit to this testing approach is that there is no chance of getting an ambiguous result: Marion will either have one of these mutations or she won't.

• If Marion tests positive for a mutation, she'll have an explanation for her family's cancer. She can alert other adult relatives of their increased risk as well as their options for genetic testing. She will also know that her daughters have a 50 percent chance of inheriting the altered gene and the cancer risk that goes with it.
• If Marion tests negative, she will know that she hasn't inherited one of the three mutations most commonly associated with breast and ovarian cancer in women of her ethnic background.

Her Test Result

Marion tests negative for the mutations multisite analysis is designed to detect. Marion realizes that her negative result does not explain her breast cancer or lower her risk for other cancers, but she's glad she had this test. Her test result means there is a much lower chance that a BRCA mutation runs in her family — though it does not entirely rule it out.

Since Marion was only interested in finding out whether she had one of the mutations most commonly associated with individuals of Ashkenazi Jewish descent, she now feels that she has closure regarding her family history. So she decides not to pursue other testing at this time.

Now that she has tested negative for the three mutations, Marion can discuss with her doctor whether or not to pursue ovarian cancer screening.