Her2/neu 3+ but FISH says negative

Is anyone on this board faced with this weird set of pathology stats. Grade 1, cribiform, diploid, low S-flow, ER + 95%/ PR + 20%, node negative. Had a large tumor; core biopsied FISH Her2 negative; neoadjuvant and got over a 50% shrinkage. Tumor pathology report came back the same as core biopsy except the Her2/neu was positive at 3+ (IHC test). Am currently beginning radiation. Oncologist believes FISH is right. Will start Tamox after radiation. Wish I knew for sure. For those of you who may have (or had) this kind of conflict, I would like to hear from you.

I think the gold standard for determining Her2 status is FISH analysis. If the FISH says Her2-, I'd be inclined to think that is correct.You also mentioned that the path report of other biological markers of the tumor were "low S phase (more slowly dividing) & diploid (normal number of chromosomes)vs. a high S phase -very rapidly dividing- & anueploid-abnormal or too many chromosomes." Her2+ tumors are typically aneuploid with a high S phase.
If you're still concerned, ask your onc to do a FISH analysis on the tumor, so that you can compare the tumor FISH results to the core biopsy FISH results, rather than the two different test types.
Consider it GOOD NEWS to be Her2-, diploid & low S phase!!That means the tumor was slower growing, less aggressive.I am so glad to have Herceptin and will continue to take it as long as they will give it to me, but I would trade my Her2+++, Grade 3, poorly differentiated, aneuploid & S-Phase 23%(!!!)in a heartbeat!
Take good care,
Jessica
ps-if they do a FISH analysis on the tumor and your are her2+, i hope you will look into getting into clinical trial for early stage, her2+ and get on herceptin!

Thanks for your answer. My dilemma is that if the tumor comes back Her2 positive off a FISH, I had no node involvement, and the clinical trials here requires that women must have at least one node involved. My oncologist is not anxious to test the tumor; not sure why, but I have done my reading and found that Her2 3+ would be like finding Al Franken dining with George Bush in the White House. Not likely territory. I think my onc is basing that call on the entire path report, the Ameripath biopsy report that used FISH, and the lack of difference in the tumor path report except for that one thing. I will ask again and see if she pretends not to hear me.

Marty

Marty-
Isn't so frustrating how hard we have to push to advocate for our own best care?!It is your health, your peace of mind, your life...you will live with the the consequences of the decisions your doctor makes "on your behalf".Ultimately, you will be paying for the cost of the FISH analysis, not your doc, but you will go home with the peace of mind knowing exactly the Her2 status of your tumor.
Keep your sense of humor & Keep the faith!
Jessica