Deregulatedexpression of HER2 has been implicated in the development of numerous types of humancancers [5].Amplification of ERBB2 gene or overexpression of HER2 protein isone of the most important prognostic factors in breast cancer patients [3], [6], [7] Therefore,HER2 has been a target for specific breast cancer treatment with the monoclonalantibody trastuzumab (Herceptin®) which was approved in 1998 by the UnitedStates Food and Drug Administration (FDA). The gene discussed is ERBB2; the disease is breast cancer.