BRCA test question

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1openheart
1openheart Member Posts: 765
edited June 2014 in High Risk for Breast Cancer

After my DCIS diagnosis, I had both the BRCA1 and BRCA2 test run due to a pretty strong family hx.  Both of those test as well as the BART test for mutations came back negative.  My question is....do my tests being negative for mutation mean that my sister or female cousins are not at risk for having a BRCA mutation too?  Or would they need to be tested to know that for sure?

I have a second cousin who just had a bc dx.  My grandmother had bc in her thirties and died from mets in her fifties,  her brother (my cousin's dad) and her sister (my great aunt) all had bc.  So, by virtue of my BRCA tests being negative, does that mean that hers would be negative as well?   Would her sister need to be tested?

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  • CLC
    CLC Member Posts: 1,531
    edited April 2012

    It is entirely possible to have a gene run in a family but someone be lucky enough not to inherit it.  So...it is my understanding that they could still be brca positive even though you are negative...though it bodes well for them!  It does mean that you cannot pass the gene to your children...:)

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  • 1openheart
    1openheart Member Posts: 765
    edited April 2012

    Thank you.

    That's what I thought.  So, my child is in the clear BRCA wise, but my sister may or may not be, correct?

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  • CLC
    CLC Member Posts: 1,531
    edited April 2012

    That is my understanding.  Of course, your children are getting genes from you and your husband.  So, if your husband had the gene, he could pass it on.  But you cannot (unless a very unusual event happens, which is a mutation within the egg...extremely unlikely).  My sole source of expertise here is I am a biology teacher.  I have no medical training...  So, I could be wrong here, but I don't think so...:)

    Glad you are negative!Smile 

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  • LISAMG
    LISAMG Member Posts: 639
    edited April 2012

    You are classified an un-informative negative, unless someone tests positive, given your strong family history. There are other un-identified genes out there besides BRCA 1/2 for families who are at high risk for hereditary syndromes. Not a fun place to be.... been there, done that too :)

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  • isee
    isee Member Posts: 105
    edited April 2012

    I had bc last year and have a HUGE family history of this disease...so I was tested for the BRCA mutation. I came back BRCA2+...so then my 3 siblings got tested. My bro is negative, my sister who looks most like me by the way, is negative, my older sis, who also had bc at 37 is also positive for BRCA2. My mom has not been tested...but obviously she is BRCA2+ as well. SO in my family with my bro and sisters...we were exactly 50%. My two kids have not been tested as we feel they should wait. Daughter is getting increased surveillance as she is my first degree relative and son will start prostate exams at 40 instead of later and will watch for chest lumps. My other positive sister had no children. So, if my kids don't have it then the mutation will have ended...in my family anyway. It will be interesting to find out if they have it or not...sure hope they don't!!!

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  • 1openheart
    1openheart Member Posts: 765
    edited April 2012

    Isee....I hope your kids are in the clear, too.

    LisaMG... Thanks for the info.  I had not heard that term before....un-informative negative. Interesting.  I looked it up to learn more.  I agree that there are probably other mutations that have not been mapped yet.  There must be when you see families with multiple members with similar cancers.

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  • cp418
    cp418 Member Posts: 7,079
    edited April 2012

    http://ghr.nlm.nih.gov/condition/breast-cancer

    PTEN and CHEK2 have come up recently in breast cancer news articles.

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  • Mutd
    Mutd Member Posts: 148
    edited April 2012

    Many uninformative negative people from high-risk families are really true negatives from the families where BRCA mutations run. But they have no way of knowing for sure, because sometimes there have been no genetic testing done in any of the relatives with cancers; or sometimes one cancer patient have been tested, but just this one women happened to be a spurious case (after all, breast ca isn't "that" rare, it strikes nearly one woman in ten even w/o mutations!).

     CHEK2 comes up often in studies, but seldom in high-risk families BTW, because its mutations don't increase the risk by a large enough factor to make a difference. Most of the carriers of CHEK2 mutations don't develop cancer. But the risk is elevated, and the reserchers begin to see the difference statistically, by comparing hundreds or thousands of patients. In a family of a regular size, one can't see a difference, the number of people is too small.

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  • LISAMG
    LISAMG Member Posts: 639
    edited April 2012

    Check out RAD51C , a newer gene for high risk !!

    http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3182241/?tool=pubmed

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  • 1openheart
    1openheart Member Posts: 765
    edited April 2012

    Interesting, Lisamg.  Thanks for posting.  It was abit technical, but I think I got the gist of it.  

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