What You Need to Know about DNA Testing Kits

You can mail out a swap of saliva to check your risk of breast cancer—but should you?

By Valerie Gorman, MD, breast surgeon at Baylor Scott & White Texas Surgical Specialists


Almost all women are concerned about their risk for breast cancer. And now, with DNA tests like 23andMe ®, it’s tempting to see if your genes put you at risk. After all, if your test comes back negative, that’s one less thing to worry about, right?

If you’re considering genetic testing, I recommend that you talk to your doctor first about the pros and cons.


What’s your risk?

When I talk to my patients about genetic testing, I start by evaluating their risk. For most people at average risk for breast cancer, genetic testing isn’t recommended. That’s because only 5 to 10% of breast cancers are linked to genetic abnormalities. So, if your risk of breast cancer is average or lower, your risk of breast cancer linked to a genetic mutation is quite low.


When testing might be the right choice

Of course, some people are at higher risk of breast cancer. That could be the case if you:

·      Have a relative who was diagnosed before age 50, or who had a type of breast cancer called triple negative, or who had cancer in both breasts

·      Have a male relative with breast cancer

·      Have a family history of both breast and ovarian cancer, or certain other cancers

·      Are of Ashkenazi Jewish descent

·      Are African American and have been diagnosed with breast cancer at or before age 35

There are other factors that can influence your genetic predisposition to breast cancer—your doctor can review your family and health history and together you can decide if genetic testing is right for you.


What testing can tell you

If after talking with your doctor you decide to go ahead with a genetic test, I recommend one ordered by your healthcare provider, since it will most likely be more thorough. As of now, 23andMe only tests for select variants of two genes linked with breast cancer, BRCA1 and BRCA2. Newer lab tests can look for harmful mutations in many genes, along with more variants of BRCA1 and BRCA2.

Plus, with a test ordered by your healthcare provider you can connect with a genetic counselor. A genetic counselor can explain what a positive or negative result means in terms of your risk, talk to you about the psychological risks of test results, and discuss your odds of genetic mutations passing forward to future generations.


What about insurance?

A lot of people worry that a positive genetic test might make it harder to get health insurance, make health insurance more expensive, or make it harder to find or keep a job.  The Genetic Information Nondiscrimination Act makes this type of bias illegal. This law doesn’t cover long-term care insurance, life insurance, or disability insurance, but other laws may offer some protection. It’s something to consider before you proceed with testing.