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Can consumer DNA kits give you helpful information on breast cancer prevention?

You've seen the ads on TV, simple, affordable home-kits that can tell you about your ancestry all with a quick spit and sendoff to a lab, but are those results helpful?

Knoxville — With growing popularity, consumer kit testing company 23andMe now offers the ability to give you FDA approved health reports as well. People are curious if these answers can help them prevent certain disease and cancers early.

You've seen the ads on TV, simple, affordable home-kits that can tell you about your ancestry all with a quick spit and sendoff to a lab.

So 10news reporter Leslie Ackerson put that test, to the test; to see if these kits are helpful in learning about your health risks as we focus on Breast Cancer Awareness during the month of October.

Results are posted online through the person's account.

THE KIT

The process is simple. You'll order your kit online and one will come in the mail in about 10 days. Just follow the quick and easy instructions and you can send it back all in one day. You can't drink any food or water 30 minutes before, then you spit into a tube, snap the lid shut tight, put it in a special baggy and back into the box. Packing labels are already attached and you send it back to their lab for testing.

Leslie's results came within a month. They were easy to access online. As well as sending off your kit, you can also fill out several family history and medical history questionnaires online to help the company better discern answers for your health.

Leslie learned she had ancestry links to the British, Irish and Norwegian, but what she was really looking for was the health risks. Specifically, that she was NOT a carrier for the BRCA1 and BRCA2 genes. Those genes are known to increase breast cancer risk.

Seems like good news, right?

Dr. Imelda Marguiles warns against making medical decision based on the kit's results.

SITTING DOWN WITH GENETICS DOCTOR IMELDA MARGUILES

"My concern was a patient would look at a negative result and think oh good I'm off the hook."

Kits like these are questionable for genetics doctors like Imelda Marguiles, who is the Director of Clinical Genetics Services at Aaron G. Marguiles MD.

"I had some reservations, I want patients to know that these type of direct consumer genetic testing may not give you the kind of information that guides medical management," Marguiles explained.

Here's a few of her concerns; 23andMe kits don't test for all genes and possible variants. They only test 3 variants out of the thousands of variants in the BRCA1 and BRCA2 genes known to increase breast and ovarian cancer. As well there are other predisposition breast cancer genes known to increase risk, with a panel of 20 or more genes may be important for the client in a clinical genetic setting.

"We go more in depth of terms of looking at the whole person and their family history, lifestyle, these factors that make a personalized medical plan," Marguiles said.

Another issue, is these specific gene mutations tested by 23andMe are only common in certain ethnicities.

In-person testing with a doctor is more thorough and will cover all the bases and get you the most accurate information.

"Our testing can be offered through saliva, but it's best through blood," Marguiles said.

SHOULD YOU GET TESTING?

Knowing if you have the higher risk is important. Dr. Marguiles says to have an open dialogue with your family, learn about your family's medical history so you can plan for your future. If you have a 1st degree relative (a mother or father) or 2nd degree relative (a grandparent) who has had cancer you have a higher risk than other individuals. An average woman's risk is 10-12 percent in their lifetime, bt if they have a first degree relative with cancer--that risk doubles.

If that's not you, don't think you are off the hook. Most cancers are not genetic, but "sporadic" cancers.

"If you were to put 100 women in a room with breast cancer, only 5 or 10 of those 10 women carry a genetic mutation, we call them hereditary cause for cancer," Marguiles explained. "The other 90 women are sporadic, environment, things they were exposed to."

While a kit may not be the best choice for a medical decision, you should stay aware.

"To people who said I did that test, I say good bring it in to me, let's discuss it," Marguiles said.

"The important thing is know your family history, talk to your providers,stay a healthy weight, exercise, eat right, reduces the risk for a multitude of cancers."

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Throughout the process, 23andMe does explain the limitations of thest and clarify with consumers that their product does not test for all variants, as Dr. Marguiles explained. They also tell the consumer that the test does NOT diagnose cancer or any other health conditions and should not be used to make medical decisions.

Dr. Marguiles explains that FDA's approval of 23andMe's reporting of the BRCA1 185delAg, BRCA1 5382insC, and BRCA2 6174delT variants has been based upon accuracy studies yielding a false positive rate less than 15% and a false negative rate less than 16% with 95% confidence.

Marguiles says if patients are willing to accept those risks of false positive and false negative, and if ANY NEGATIVE or POSITIVE findings are reported to the patient, then genetic professionals would advise the patient that medical management decisions should not be made on those DTC results without first consulting with a genetics professional regarding their detailed family cancer history/personal medical history and confirming genetic tests with a new DNA sample with a CLIA approved clinical lab.

Once appropriate genetic tests have been completed and/or confirmed, then we can provide clinical guidelines for personalized genetic cancer risk management regarding increased cancer screenings/options for the patient to reduce help their risk of cancer.

HELPFUL LINKS TO LEARN MORE:

Cancer Risk Quiz

Facingourrisk.org - Has information on Pre-vivor day and Hereditary Breast and Ovarian Cancer Awareness Week of Sept 30-Oct 6, 2018

Lynch Syndrome - March 22nd is National Lynch Syndrome Awareness Day

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