Her2

[maggiec]

Hello,

Sorry to be asking more questions about IHC postive and FISH negative but I read a post on a breast cancer support board that a reason for this could be that a part of a tumor can be Her2 negative and another part of the same tumor can be Her2 postive.
Is this possible. If so should the whole tumor not be tested each time.

I'd also like to thank for providing such a wonderful service.

Many Thanks, Maggiec

[CCF-RN,MSN-rf]

Dear maggiec:  I have spoken with experts.  The FISH test is the definitive test for HER2.  IHC has been known to show positive results and inconsistent results.  This is due to heterogenicity (dis-similar features) of staining - not heterogenicity of the tumor.  If there are positive cells, the FISH test will show it.  Being HER2 negative is a good thing - this is a better prognostic indicator than being HER2 positive, in general.

[maggiec]

Thanks you so much for this information. I very much appreciate it.