[MGordon]

Keep things sunny!!!! I'll start with the FISH tests.

It is estimated that approximately 1 in 4 breast cancers have too many copies of the HER2 gene, resulting in the over-production of protein receptors found on the surface of tumor cells. These special proteins bind with other circulating growth factors to cause uncontrolled tumor growth. HER2 positive breast cancers tend to grow fast. But these tumors also may respond very well to anti-HER2 antibody therapy (our friend Herceptin) and also to increased doses of chemotherapies.There are two tests for HER2, IHC (ImmunoHistoChemistry) and FISH (Fluorescence in situ Hybridization). The IHC test looks at the protein on the surface of the cell by staining the cell with an antibody. The protein on the surface of the cell can be affected by tissue formalin fixation onto the slide. This can cause inaccurate interpretation of IHC results. In addition, IHC testing is subjective: the reader must judge the degree of color change in the cell against a non-standardized chart. The fluorescence in situ hybridization test (FISH) is more accurate and reliable. It is good for all kinds of tissue: fresh, frozen, and those formalin fixed, paraffin embedded tissue. It is also good for stored formalin fixed paraffin embedded tissue samples too. The FISH test measures HER2 gene abnormality at the stable DNA level. The FISH test "paints" the HER2 genes inside the cell, so they may be accurately counted.

Clear as mud? FISH kinda removes the "human error" component to the test.