IHC vs Fish? different results?

saintsim

I'm so confused with my wife's HER2 test results on original breast cancer tumor.

IHC is 2+ and Fish no amplication. Is this possible? I thought Fish should give some number as it's positive if the number is over 2.2.

Now I'm gonna ask to retest HER2 on the tumor removed from her C-7 spine a year ago and another tumor removed from T5-6 four weeks.

My hope is these retests may come out positive so she can try herceptin and tykerb as our onc doc says no chemo for mets on meninges based on our previous fish negative on the original tumor.

Now she's getting WBRT on her brain and no further treatement plan. I don't want to give up and needs more info about HER2 tests.

 Especially, how I can raise my chance to ask for retests of HER2 on the new spine tumors to get the any of best chemo treatment for her.

 Please I can't give up on her like this...Just need more time to prepare for the last....Thanks

dlb823

saintsim ~ I wanted to pass along an article that appeared in the New York Times last year, as well as a later article about it: 

http://www.nytimes.com/2010/04/20/health/research/20cancer.html

http://annieappleseedproject.stores.yahoo.net/amcopaassets.html

As you've figured out, it's imperative that her Her2 be properly identified.  Perhaps these articles will give you the amunition you need to confront her doctors or find new ones, if you believe either of those is necessary.   Deanna

orange1

You could try this study as an argument:

In this study - all classes of tumors that showed evidence of Her positivity (IHC 1+, 2+ 3+ and FISH+) benefited significantly from Herceptin, including tumors that scored IHC 1+ or 2+ and did notsubsequently test positive by FISH testing. From Journal of Clinical Oncology, 2007 ASCO Annual Meeting Proceedings (Post Meeting Edition).  Vol 25, No 18S (June 20 Supplement), 2007: 511AbstractBenefit from adjuvant trastuzumab may not be confined to patients with IHC 3+ and/or FISH-positive tumors:  Central testing results from NSABP B-31S. Pal, C. Kim...others511Background: 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 determined 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.