does anyone know what the levels mean
 

My onc told me that my FISH assay came back as 17 mean and 6.5% but then breezed on to another topic. What does that mean? Any one know.

HER2 amplified
 

Fish is a test that looks inside the cells for how many copies of Chromosome 17 there are as well as how many copies of the HER2 gene there are. (It is called a "gene amplification" test.)

The mutation with HER2 positive cancers has to do with extra gene copies inside the cancerous cells.

I was tested a positive +++ by the IHC, which is a different test, so do not know my FISH number. If a person is HER2+++ (no doubt strongly positive) by IHC they often do not run the FISH as well.

Your number of 17 most likely means that you are strongly HER2 positive by FISH, which is actually a good thing as the patients with more strongly positive HER2 cancer normally respond better to Herceptin and the drugs that are synergistic with Herceptin.

Maybe some others who had the FISH assay will also answer as to your number and percentage.