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Fish test?

Fitmom04 Member Posts: 40

Yesterday I got diagnosed with Breast Cancer, Invasive mammary carcinoma. She said that not all results were in. The ER was low positive, PR was negative and waiting for the HER2 but they had to do another test, a Fish test? Anyone know what that is?


  • specialk
    specialk Member Posts: 9,236
    edited July 2022

    FISH stands for Flourescence In Situ Hybridization and it is a test that check to see if your breast tumor overexpresses Her2 genes. Sometimes pathologists run this test initially, other times they use a less expensive testing platform more similar to the ones used for the ER and PR - which is IHC, and if the result is not clear cut they then run a FISH test. Sometimes these tests are send outs if the lab does not have the testing equipment, so it can take a bit longer, but it is a normal part of the pathological workup.

  • moderators
    moderators Posts: 8,283
    edited July 2022

    Thanks SpecialK! Yes, Bohartois, SpecialK explained this perfectly. For more information, see FISH Test. Also, here is some info on the IHC Tests.

    We hope this helps!

    --The Mods

  • bluegirl27
    bluegirl27 Member Posts: 28
    edited August 2022

    I am currently awaiting my FISH test results after SMX and pathology showed ER/PR positive and HER2 came back as 2+ equivocal all on IHC testing. So they sent HER2 off for FISH testing. I am hoping it comes in this week.