Talking About Breast Cancer Risk

Editor’s note: Pending an FDA decision, 23andMe no longer offers new customers access to health reports referred to in this post. Customers who purchased prior to November 22, 2013 will still be able to see their health reports, but those who purchased after that time will not. Those customers will have access to ancestry information as well as access to their uninterpreted raw data.

Angelina Jolie’s revelation in the New York Times today that she had a double mastectomy after learning about her genetic risk for breast cancer focused attention on the difficult dilemma faced by many women in similar circumstances.

Jolie said she decided to write about her case to help other women.

“I chose not to keep my story private because there are many women who do not know that they might be living under the shadow of cancer. It is my hope that they, too, will be able to get gene tested, and that if they have a high risk they, too, will know they have strong options,” she wrote.

The revelation has also prompted some of our customers to ask about what 23andMe reports concerning breast cancer.

First 23andMe’s test is not diagnostic. Our report on BRCA1 and BRCA2 looks at three mutations in those two genes associated with breast cancer. We have another report that looks at eight other mutations in other genes or gene regions including CHEK2, FGFR2, CASP8, STXBP4 and TAB2. The information concerning those mutations help us calculate risk, but also can inform people whether they carry the mutations associated with breast cancer that can be passed onto children.

Finally, we inform customers that the absence of the mutations does not rule out the possibility that they may carry another cancer-causing variation in one of those genes.


  • Lona

    So when one gets tested with 23andMe does that cover BRCA1 and BRCA2. Meaning can one just do the 23andme test instead of BRCA1 and BRCA2?

    • ScottH

      Lona, 23andMe’s test is not diagnostic, nor does it by any means cover all the genetic mutations that have been identified to be associated with a risk for breast cancer. There are many, many different mutations within both BRCA1 and BRCA2 that are associated with breast cancer. There are also other mutations in other genes and gene regions that are associated with breast cancer. And there are additional unknown genetic factors that influence risk for the disease. 23andMe tests for three mutations in BRCA1 and BRCA2 that are associated with the disease. In addition we report on eight other mutations in other genes or genetic regions that are also associated with breast cancer. These are by no means the only mutations associated with breast cancer.

      • Jen S.

        ScottH: Your response was more suscinct than the Blog post. Thank you. As I understand your response, if I receive information on mutations in those 10 (?) genes I should schedule an appointment with the appropriate physician to discuss probabilities and options.

      • Lona

        OK great! Thanks Scott. What you are saying is that in order to cover all the bases do not just stop after the 23andme test.

  • Camille

    Lona, I have tested with 23 and me. I believe the three gene mutations are connected with Ashkenazi Jewish ancestry. That doesn’t mean even if you don’t believe you are Jewish that you don’t have them, but that was the largest sample they have and as identified genes easier to test.

    I would recommend talking to family members if they are available. If anyone had breast cancer fund out if you can if they know the specific genetic mutation. If you don’t have access to this information, or once you have this information, you can contact a genetic counselor.

    I was adopted, and I had found out when I first met them was that breast cancer was spread out through the family. I spoke with my one aunt who had testing done and she was able to find her paperwork with the specific gene on it. I took that to Penn Medicine and they were able to do genetic testing to determine whether or not I had it. I thank God that I did not, but I am very happy that I went and had the testing done.

    Please let me know if you have any questions I would be happy to talk to you about my experience.

  • CM

    At most, I would consider a positive result for the mutation on a 23andme test cause to talk to a physician about getting the test done by Myriad Genetics.

  • Cyndi

    Hi, thanks for the article. Very timely. There is a bug with it though. I went to the two reports you link to, the main one with 3 BRCA mutations and the other with 8 other mutations. Even though I logged into my 23andme account (and my name appeared on top instead of “sign in”), it only showed results for one of the Mendels (the sample reports in other words).

    If I go into my account and choose Health and Traits, I can then navigate to the BRCA report and see the results for me and the family members whose tests I administer. But I can’t find the other report. The one that is supposed to be here (this version only gives the Mendel report):
    https://www.23andme.com/health/Breast-Cancer/

    Thanks!

    • ScottH

      Cyndi,
      Thanks for the note. The links in the posts are links to the reports that are open to anyone whether you are a customer or not. For those who are signed into their account the report that looks at the mutations in BRCA1 and BRCA2 you go here. The report that looks at the eight other mutations in different genes or gene regions is here.

  • anastasia

    Sorry, I am probably the only one confused. when u say the test is not diagnostic, does it mean that there is another, more extensive genetic test? So, in other words the 23 and me can’t really tell if person has brca1 and brca2 mutations? Or, can it? In another article about AJ she mentions that tesing for these mutations cost about 3K, and I know that genetic sequencing is petty expensive, so just wanted to see what 23 and me does compared to thi type of genetic testing. Thank you!

    • ScottH

      Anastasia, Our test is not the same test she used. We do a risk calculation based on three mutations in those two genes, BRCA1 and BRCA2. There are literally hundreds of different mutations in those genes — and in other genes and gene regions — that may contribute to a person’s risk for getting breast cancer. While the three mutations that we test for are strongly associated with breast cancer risk, they are not the only mutations that contribute to a person’s risk for getting the disease. For more about our test and what we report on please go to 23andMe.com. Thanks.

  • KH

    Hello, now that the Supreme Court has decided that genes cannot be patented, will 23andMe begin testing any additional SNPs on the BRCA1 and BRCA2 genes that were previously unavailable because of the patents? If so, when could we expect analysis of these additional SNPs to be added? Thanks.

    • ScottH

      We do plan on adding additional SNPs to our report, but this is not related to the Supreme Court decision.

      • SB

        ScottH, can you please explain a little why the Supreme Court decision isn’t affecting your plans with respect to BRCA1 and BRCA2? I’m sure I’m not the only one surprised to hear you say that.

        • ScottH

          That’s not what I said. I said we do plan on updating our BRCA1 and BRCA2 reports, but the updates are not related to the court decision.

  • Joseph Katzinger

    Hello,

    Hello ScottH,
    I recently received a response from 23andme about the 3 specific mutations covered in this test, which is as follows..”The 80-90% of the hereditary breast and ovarian cancers are due to the three mutations that we report on. It is also important to note that only five to 10 percent of breast cancers occur in women with a genetic predisposition for the disease”

    Thus it appears that nearly 90% of all breast cancer cases WITHIN the brca1 and brca2 genes (which are known) are due to the 3 mutations checked, i.e. only 10% of breast cancer caused by mutations WITHIN these 2 genes would not be assessed by the 23andme test. If correct, this seems like a fairly sensitive test.

    • ScottH

      It is correct that the three mutations 23andMe currently covers account for a large fraction of BRCA-positive hereditary breast and ovarian cancer cases. However, these mutations are most common in people with Ashkenazi Jewish ancestry. In people without Jewish ancestry with a family history of breast/ovarian cancer, other BRCA mutations are most often involved. Restricted to those without Ashkenazi Jewish ancestry, then, sensitivity would be considered much lower.

  • jude

    what I’m not seeing mentioned here is what is up w/all the mutations…shouldn’t that be a pertinent question? why do so many women have mutated genes in the first place?

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