role of herceptin

is herceptin indicated in ihc3+ fish not amplified but showing polysomy
sanjiv

[Cleveland Clinic]

Dear sanjiv,  The role of Her-2 testing of breast cancer cells is to determine which women will derive benefit from the use of the drug Herceptin.  Herceptin binds to the “Her-2 Receptor” on the surface of cancer cells to cause cell death.  The chemotherapy Hercepin only works if the Her-2 receptors are present on the cell surface.  Imagine the receptor as a keyhole and Herceptin as the key.  Without a keyhole, the Heceptin cannot work.  

Unfortunately, the methods for predicting potential response to Herceptin (IHC, FISH etc) are imperfect.  The landmark studies that support the use of Hercepin chose women with Her-2 positive tumors as defined by IHC 3+ or FISH positive (greater than 2.2).  We are learning that some women with discordant results in Her-2 testing still benefit from Herceptin.  While FISH testing may be more “accurate”, there are studies suggesting women with IHC positive, but FISH negative tumors still benefit from Herceptin.  

There is no perfect method for predicting whether or not you will benefit from the added Herceptin.  However, based on your 3+ IHC testing, you would have been allowed to participate in the clinical trials that demonstrated women who received Herceptin lived longer.