who are her2 positive?

Hi vivo -

There are 2 commonly used methods for testing Her2 status: IHC and the FISH test.  IHC is relatively inexpensive to do, but is hard to interpret and may be subject to error.  The FISH test is more reliable, but more expensivie.

Typically, tumors are tested by IHC and results fall into these catagories

0 = negative

1 = usually negative

2 = uncertain

3 = positive

Her2 (2+) is sent out for FISH testing to confirm results (a few institutions also send out 1+ results too.

About 75% of the time, tumors testing IHC 2+ come back as negative on FISH testing and are then considered negative.  About 25% of the time they come back as positive.  This was the case for me - I was IHC 2+ and came back FISH positive, so was eligable for Herceptin. 

Very important for you:  In the early days of Her2 clinical trials, they did not have reliable Her2 testing.  After the trial was over, they went back and looked at results after retesting tumors.  It turns out, that tumors that had tested positive for Her2 BY ANY METHOD, FISH or IHC regardless of degree of positivitey (even 1+ and 2+ tumors that did not subsequently test positive by FISH), had a significant benefit from Herceptin.  So no way would I go off the Herceptin.  if you PM me with your private email address, I will scan the article abstract for you and email it (I can't post scanned articles directly here).

Based on my understanding, you are likely to benefit from Herceptin. 

I mis-spoke in my previous post.  This data comes from a Herceptin study that was testing Herceptin in the  adjuvant setting, not the metastatic.  But I see no reason why it wouldn't apply to the later stage as well, since the test methods are the same in both settings.  Since I can't sleep anyway.  I'll type it in:

From Journal of Clinical Oncology, 2007 ASCO Annual Meeting Proceedings (Post Meeting Edition).  Vol 25, No 18S (June 20 Supplement), 2007: 511

Abstract

Benefit from adjuvant trastuzumab may not be confined to patients with IHC 3+ and/or FISH-positive tumors:  Central testing results from NSABP B-31

S. Pal, C. Kim...others

511

Background: Trastuzumab is a humanized monoclonal antibody targeted to HER2 protein and currently indicated for Her2 positive breast cancer defined by overexpression of Her2 protein (3+ IHC staining by HercepTest) or Her2 gene amplification (Her2/CEP17 ratio over 2 by PathVysion FISH assay).  These criteria were determined for advanced disease but have not been formally tested in the adjuvant setting.  We examined these tests' ability to predict benefit from adjuvant trastuzumab in NSABP B-31.  METHODS:  All available tumor tissue blocks from the B-31 trial were sujected to HercepTest and PathVysion assay as defined in the B-31 protocol.  Formal statistical test of interaction between HER2 levels measured by these two tests and benefit from trastuzumab was performed.  RESULTS: 207 or 1795 cases (11.5%) showed gene amplificiation as as determined by PathVysion, and 255 of 1662 (15.3%) showed overepression as deterined by HercepTest.  161 of 1662 (9.7%) had neither gene amplificiation nor overexpression  There was a consistent benefit from trastuzumab in every subset defined by IHC or FISH.  No statistical interaction was found between DFS benefit from trastuzumab and level of protein (p = 0.26) or Her 2 gene copy number (p=  0.60).  Benefit was observed in patients with tumors that were negative for FISH and had less than 3+ staining intensity on IHC by HERcepTest (RR= 0.36, p = 0.32).  CONCLUSION:  Current definition of HER2 overexpression/gene amplificiation based on data from adjvanced disease may need to modified for the adjuvant setting.

In all categories of Her2+, regardless of degree or how measured, relative risk with Herceptin was less than half of what it was without.  And all results were highly statistically significant, meaning results were likely not due to random chance. 

hi my name is paul and I live in new zealand, my wife is called wilma and I would like to contact orange 1 as I am confused about what has happened to my wifes treatment. Our e-mail is nixon.family@slingshot,co,nz I am not sure how to send an e-mail threw this board.

Hi vivo: I thought that at some point you were considered Her2 postive.  That means at some point a test result must have come back at least slightly positive (IHC 2+).  Based on this slight degree of positivity, If it were me, I would continue with Herceptin, and try any other Her2+ drugs available to you such as lapatinib or TDM-1 trial if you can get in.

I do not think you should have the tumor checked. 

I was trying to say that based on the article I sited above, since your tumor tested somewhat positive for her2+, with any test method, and then later tests negative with a different test method, that Herceptin still decreased risk the study sited above so may be of some benefit to you.

Sorry for the confusion

Brazos I would ask why you were not tested. All breast cancers should be tested for HER2. If you insurance won't pay for it you or your doctors can contact the companies that do the test and they can help.