[Interaction between specialties: dilated cardiomyopathy and HER2-positive breast Cancer].

Basic research may result in unexpected benefit in terms of progress in the understanding of mechanisms responsible for different diseases and their potential treatment alternatives. This is seen, for instance, when a specific situation, defined in clinical practice, may be translated into laboratory findings which suggest a new therapy for an unrelated disease, representing the inverse of the more usual bench-to-bedside path. During the past few years, the use of the monoclonal antibody trastuzumab, in the adjuvant and therapeutic context, has become of fundamental importance in the treatment of breast cancer with amplification/overexpression of HER2, resulting in significant increase in survival rates. The observation that trastuzumab also induces cardiotoxicity, and the identification of mechanisms involved in this side effect, have allowed the investigation of these factors as a therapeutic alternative for dilated cardiomyopathy, in a highly interesting fashion.