Low HER2 (-) Negative (1+ instead of 0)

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thria157
thria157 Member Posts: 37
edited November 2019 in Stage IV/Metastatic Breast Cancer ONLY

Hi all,

My mother has been diagnoses with HR + and HER2- the last 16 years the last 7 with MBC.

The last two years her HER2 is still negative but its 1+ which means is not 0.

Therefore the ONC said that that she has some tissues that responsive to endocrine therapy and some other that are not and they need chemo.

He said that this is a new type of classification because in the past was everything classified as HER2 positive or negative.

He also said that there are new drugs coming out for this specific low HER2 that is still negative but has some tissues that are HER2. Such as the DS8201.

my mother has MBC on bones mets the last 7 years and small liver spots the last 4 months.

She was on endocrine therapy and the TM was declining a lot but the tissue in the liver grew by 20% in 3 months, so we decided to do chemo.

I am just wondering if there are any other cases with this low HER2 1+ and whats their experience and plan of action

Thanks so much

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  • JFL
    JFL Member Posts: 1,947
    edited July 2019

    Wow, her doctor is pretty open-minded. I have been HER2 negative (+2 or sometimes referred to as "equivocal") and have been trying to get on some sort of HER2 treatment since I was originally diagnosed in 2006. No luck to date although I have not given up. I am also watching DS-8201 given that it is being used to target HER2-low BC. I have not heard about a new classification of HER2-mixed as you describe but it makes sense. Tumors are so heterogenous, that different parts have different expressions of hormone receptors, HER2 receptors and other markers. For what it is worth, I am on both chemo and hormone therapy right now, as sort of an alternative treatment. My MO wanted the tamoxifen for my bone mets (which never became hormone therapy resistant - the only time my bones progressed was when I was recently on a clinical trial targeted therapy FGFR inhibitor that just didn't work at all), while the chemo is likely helping keep my liver mets in check. My liver mets have progressed many times. Please post more information if this HER2-low or HER2-mixed issue develops further with your mom's doctor and treatment plan.

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  • thria157
    thria157 Member Posts: 37
    edited August 2019

    Hi There,

    Thanks for you response. From my understanding is low simply because her bones one is hormone responsive, but also the liver mets, when she did the biopsy also came up as hormone responsive, but affinitor didn't decrease the tumour but decrease the Tumor marker a lot.

    Are you doing tamoxifen and chemo an the same time? My mothers ONC believes that Abraxane will work for both hormone responsive and non.

    Was that the case for you ?

    Of course I will update this post frequently and I am more than happy to share any info I found.

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  • arolsson
    arolsson Member Posts: 118
    edited November 2019

    So thankful to find these posts! I am completely bewildered. It seems like the most basic and important question to ensure proper treatment is "what type are you". I was a straight up ER+ PR- HER2- on the first go-round at stage IIIB 2012-2014. Same when diagnosed metastatic 2017 in lymph nodes in my chest and in my bones. (2+, positive FISH) When it spread to my liver last year they did a liver biopsy and pronounced me suddenly ER-PR-HER2+ . Out with the estrogen blockers, in with the Herceptin. Failed miserably on TDM1 (Kadcyla) and was put into the TULIP trial for SYD385, a new conjugate. Now off the study because the central lab in Holland says they've tested twice and I am clearly NOT HER2+ but a 2+ with negative ISH and low HER2/cr17 ratio.

    Starting Halaven (eribulin) and wondering about next steps. Can I really be typed so differently from the same liver biopsy? Apparantly so...

    There doesn't seem to be much else left to try after the Eribulin so fingers crossed. Best to all from Sweden!/AMY

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