Curious...What was your FISH?

In 2002, I was diagnosed with a 2.4cm IDC, negative nodes, ER+, PR+ and IHC 3+. At that time, I did not qualify to enter the Herceptin clinical trials. When all the good news about Herceptin started to come out, I decided to start "late" Herceptin. I started Herceptin 2 years after my diagnosis.

After my first Herceptin treatment, I had many side effects. Being a Medical Technologist, I knew about the FISH test and asked to have it done just to double check I was actually Her2 positive. After weeks (and 2 more Herceptin infusions), my FISH test came back negative (1.5).

My original IHC test was done at a local hospital lab. (I switched to a large breast cancer center after diagnosis.) The pathologist at the local hospital admitted that in 2002, the IHC test was new for them and they didn't do many of them. They found out they were getting quite a few false negatives and false positives. In 2003 because of this lack of compliance, the lab changed the way they were doing the IHC test.

After getting many opinions, I was told that if you are really IHC 3+ and FISH negative, you can still benefit from Herceptin. The tests are measuring two different things. IHC tests for a protein on the outside of the cell. FISH measures the genetic material inside the cell. IHC can be done in most hospital labs but FISH, a more expensive test, needs to be done in a reference lab. IHC has more varibles for error and also is a more subjective test than FISH.

I stopped the Herceptin and asked to have the IHC repeated. After more weeks, I was told that the local hospital lab could not give me and "accurate" IHC result because the tissue sample was too old. I believe in my case the original IHC test was done incorrectly--I am not Her2 positive and never was. I'm very glad I did not go through a year of Herceptin for no reason.

I know I am a very rare case. It does seem scary to make such a large commitment of a year of treatment when there are still questions about the accuracy of Her2 testing.


So as Saleboat said, "it may make a lot of sense to have one's pathology done by a high-volume lab that has a lot of experience with these two tests."