Genetic Testing - Repeated???

cindy0519
cindy0519 Member Posts: 173
in Uterine/Endometrial Cancer #1

Has anyone had genetic testing repeated?  I had BRCA1 & 2 testing done when I was diagnosed with Breast Cancer in June 2015. They also did an expanded panel for gene mutations that they really don't know much about yet.  All of this came back clear.

When I was diagnosed with UPSC in Sept 2014 I also had a test performed for Lynch Syndrome.  It too came back negative.

Since my testing my sister had been diagnosed with Uterine Cancer (caught very early - Thank God!) and I just had two precancerous polyps removed during my colonoscopy. One that was a 7mm sessiel serrated polyp from my promixmal traverse colon and one that was a 14mm tubular ademona with high grade glandular dysplasia from my sigmoid colon.

I know there can be false positives on these test.  Can there be false negatives?????  Part of me wants to make an appointment with the Genetic Department at my cancer center again since my intital test were done with only the breast cancer being a known factor at the time.  Anyone done this type of thing before? 

 

Comments

  • Kvdyson
    Kvdyson Member Posts: 789
    edited December 2016 #2
    Cindy, I just read this from

    Cindy, I just read this from a daily medical newsletter (called Stat Morning Rounds) and thought that it might provide you with some useful information about the question you pose:

    Cancer gene sequencing tests turn up disparate results

    Two commercially available genetic sequencing tests can turn up wildly different results in the exact same cancer patients, calling into doubt how much physicians should be relying on them to guide treatment decisions. New research in JAMA Oncology analyzed results from two genetic tests, FoundationOne from Foundation Medicine and Guardant360 from Guardant Health. Researchers had nine patients from a cancer-care practice take the two tests. One patient didn’t have any genetic alterations turn up in either test. But for the other eight — who had 45 genetic mutations in total — just 10 mutations were picked up by both tests. And the tests often disagreed: For two individuals, there was actually no concordance between the results. The study’s authors say they’d like to see follow-up comparisons done on test results in a larger group of patients.

     

  • takingcontrol58
    takingcontrol58 Member Posts: 272 Member
    #3
    Genomic Testing

    The important thing to remember about genomic testing is that each company tests a different number of genes.
    Foundation One tests 315 genes.  It appears to be the most comprehensive, and I believe the NIH is now
    working with them.  Guardant only tests 73 genes, plus 47 amplifications, fusions and indels (120 in total).

    This may account for the discrepency in your testing.  I don't think many people are finding out all their
    mutations because the doctors aren't always testing for all the relevant mutations to their specific cancer.  I have
    one of the most popular mutations in endometrioid adenocarcinoma, but it is not listed in the Guardant list of genes.
    My testing was done through Foundation One. A second mutation I have is also not listed in the Guardant testing.
    Both companies list the genes they test on their websites.

    Hope this is helpful.

    Takingcontrol58

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