Tumor both HER2+ and HER2-

[SunCrystal]

Is there anyone else whose tumor was diagnosed as heterogenous with HER2+ and HER- sections? My biopsy sample was HER2+ but following my mastectomy surgery, the tumor itself was found to be HER2-. Both pathology labs conducted FISH. I had the FISH tests repeated at a 3rd independent pathology lab and they obtained the same results with HER2+ for the biopsy sample and HER- for the mastectomy tumor. I know this is pretty rare--but I am wondering what others' experiences have been and what treatment was recommended. My oncologist just started me on herceptin and taxol a week ago after 4 dose-dense AC treatments.

[CoolBreeze]

Honestly, I've never heard of that. I was going to say you should get your tumor retested but it seems you have.

I think the treatment is appropriate though. Treating as if you were fully HER2 won't hurt the parts that don't overexpress the protein but will help the parts that do.

You are one complicated lady! :-)

[Sheila]

Could it be possible that there was 2 tumors? Small, but indiviual? I say this because my sister was triple neg on one tumor and triple positive on the other in one breast...just a thought>

[karen z]

All responses to your posts been great and, boy, this is complicated. I think your oncologist is being appropriately aggressive given the situation (and it was very smart to be retested more than once if necessary). Yours is not an easy regimen (most of us have not had easy regimens but they do end) but it is highly effective for whatever part of anything is HER2 positive (which is critical to deal with). I had the same regimen as you but did not have dose dense AC, just "regular" AC. Best of luck and please ask this group if you have any more questions. You will find a lot of wise people here! I know I have!

[SunCrystal]

Thanks for the responses. It was just 1 tumor, not 2. And I am glad that the independent pathology lab was able to confirm the HER2 in their testing--and not writing it off as a false positive. I wouldn't want to be HER2+ and NOT have herceptin. It will all be good in the end, I'm sure.

[NanaJoni]

I also had 2 small tumors - one triple negative and one er-/pr-/HER2+++. So I did TCH and then Herceptin for almost a year. Really unusual to have path results like yours but I'm never surprised by anything these days.

[Rich66]

Good example of the limits of limited biopsy sites. My mom's presurgery needle biopsy referred to heterogeneous mix regarding Her2. If you can have different results within one tumor, it is probably not so rare for multiple met sites to have different characteristics. Did you happen to have neoadjuvant/pre surgery chemo?