fish test is HER2 positive but Foundation test HER2 negative

lynn2161

Diagnosed with bone mets almost three years after initial Stage 2B breast cancer. . Initial pathology of the bone mets showed HER2 equivacol. FISH test showed HER2 positive. My second opinion doctor ordered the Foundation test. Test came back saying HER2 negative.

I have already had 2 treatments consisting of Taxotere, herception, and perjeta, given the original results of HER2 positive. Has anyone had conflicting results on HER2?

carmstr835

Yes. I had a needle core biopsies done March 13th for bilateral BC. It was equivocal for my right breast but the FISH came back negative, eventually on my left breast. The right, eventually came back as +3, IHC but equivocal on the FISH test. I informed my Dr.s of this result back on March 25, since I had switched treatment centers after my biopsies. I sent them copies and gave them access to the results. I was never satisfied with the lack of concern I received regarding my +3 status of the Her-2 at my new treatment center. I assumed they knew what they were talking about, even though I never got a satisfactory answer to my questions. They seemed to believe the surgery pathology trumps the biopsy. Genotype or Onca score said negative Her-2, but I know those are not FDA approved for Her-2 status results. The problem was I was being treated with Arimididex prior to my surgery so the pathology is tainted...

I decided to do a 2nd opinion at yet another treatment center, in May they were very interested in the biopsy pathology and set out to redo it all, but said it would take a while waiting for the specimens and such.

I have since been treated at the cancer center as though I am Her-2 negative even though some of my Her-2 status states unknown. I got the message just today from my 2nd opinion. They have the results and it is Her2 +3 not sure what test, but they are confident it is NOT a false positive. I have had 2 chemo treatments already, can they add the hermceptin to my regime now after 2 treatments? Will they? The Dr is to call me this afternoon to tell me his thoughts. He stated this is very complicated... Let know what your doctors decide, I will let you know whatn they say for me. I am concerned though, I thought I was 1/2 way done...

meg2016

I am not stage IV, but I did have conflicting results on my tests. They chose to treat as her2+, some evidence that herceptin can be beneficial even if not strongly her2+.

lynn2161

Hi there,

What test showed HER2 negative if the fish test showed positive?

meg2016

I am not sure what the secondary test was, honestly. I was qualifying for a trial and so they had to do complete scans on me as well as redo all my pathology. They used a different test for HER2 when they redid it. So my MO said it could be the test, it could also be a different sample of tissue having a different result. When I tested negative the second time, it disqualified me for the trial, so then things got crazy with me trying to schedule chemo instead, etc etc. so I didn't spend a lot of time researching it. But we did move forward with Herceptin and Perjeta.