Positive or Negative???

Hi KEW and Kitty -- I saw your posts here and wanted to say hi.  I actually don't have answers for you, Kew, but am curious to see what people who know have to say.  Were you given a path report on your actual breast tissue at time of BMX?  (Sorry there's a lot to follow here).  Your original diagnosis was based on a core biopsy... which is a smaller sample.  What seems odd is that you even went to the trouble of getting a second opinion on the pathology in April 09 and still no one said anything.  It may have to do with the FISH report, though, which not everyone gets and which gives more/finer detail/info than plain old HER2 test (if I remember right).  Sorry I can't be more helpful.  I'll mark this thread though and keep up.

Hi - this is a complicated issue.  FISH is more accurate than IHC.  However, false positives and negatives can occur.  I was 1+ on IHC and a ratio of >5 on FISH, so HER2- by IHC and HER2+ by FISH.  My onc (who is part of Dennis Slamon's research team, so they know their stuff wrt HER2) treated me as HER2+ and I went in clinical trial, receiving neoadjuvant TCH+Tykerb.  I had several additional core biopsies as part of trial protocol, and FISH was done on those samples and I was HER2+ on those as well. 

Originally my tumor was ~2.2x2.5x1.5 or so cm on MRI.  The path report from my MX showed that >80% of the original was now gone, what remained had isolated patches of tumor, none greater than 4mm in size.  The cancer cells that remained were damaged by chemo.  But what is interesting is that the cancer that remained was HER2-.  So my tumor was heterogeneous wrt HER2 status, and it is becoming more widely accepted that this is possible.  Maybe that is going on with you as well, or maybe you had false positive or negative (depending on which you believe) findings.

I'm very happy my initial core biopsy FISH results were from one of the HER2 + sections of the tumor - this meant I got Herceptin right away.  Like Tricia says, you definitely want Herceptin if any of your tumor is HER2+

Good luck!!!

Hey Drim - interesting story - so glad you got the HER2+ portion sampled and are getting the appropriate tx!

My core biopsy was 1+ on IHC, but sent for FISH testing by the pathologist.  Good thing.  It came back 6.1, definitely positive.  I was shocked.  One minute I was wondering if I could avoid chemo and the next it was ACT and a year of Herceptin.  How many pathologists report IHC1+ as negative and let it go at that?  I feel like I dodged a bullet. 

Hi I am new to these boards and have so much confusion.  My pathology came back as ER + and PR + and HER2+1.  Do you all think that the FISH is a more reliable source than the IHC?  I have no node involvement and was really hoping to avoid Chemo.  I want to do the right treatment.  I am 45 and premenopausal. 

The "standard of care" is to send IHC 2+ tumors out for FISH testing, and call IHC 1+ tumors "negative"  However, as lovetosail points out, occasionally IHC 1+ tumors turn out to be positive.  If your tumor is in fact positive, then you are at much higher risk of early recurrence, but will not get the chemo/herceptin that would greatly reduce that risk.

Also, I saw from your previous post that you had multiple tumors in one breast.  Multiple tumors are especially common in Her2+ cancer.

If it were me, I would have the tumor sent out for FISH testing even if only IHC 1+, even if I had to pay for it myself.

Lana- 

I neglected to answer your question. Yes, FISH testing is more reliable than IHC testing.  IHC testing for Her2+ is very sensitive to sample hold time before preparation, sample preparation itself and is somewhat subjective.  

I was IHC 2+, but had greater than 10 gene copies - a very highly positive result.  I also had multiple tumors.