We are still learning a lot about how to use assays and which assays, which tests, can truly determine whether a tumor has excessive amounts of this protein HER2 or not. And we run into trouble with what we call false positive when we say that the tests show this excessive amount when there is none and therefore we may consider offering a drug to a woman who s not going to benefit from it and may have side effects of the treatment. Or the opposite, a false negative when we have excessive amounts, of the protein, but we fail to detect with the test and therefore we end up not offering to a woman medication that she can be helped with. A lot of the problems with the test have to do with lack of what we call standardization. A lot of pathology laboratories have been using their own cocktails of tests to determine HER2 testing, and therefore there s a lot of variability of the results from one laboratory to another.
Immunohistochemistry is very easy.
Pathology labs are very used to doing it. FISH is more expensive, it s more time consuming, and it s more technical. Whether one is better than the other, there is suggestion that the FISH test may be better. So, I think these are ongoing questions and many clinical trials are addressing that question, specifically. I do not think that this is going to be a major issue in a couple of years when we have standardization of them.