ABSTRACT The development of resistance to chemotherapy, endocrine therapy and anti HER2 agents in breast cancer is an important and common problem that impacts in the management of patients, particularly in the metastatic setting. This resistance has been explained in part by the activation of signal transduction pathways, including the PI3K/AKT/mTOR. The blockade with mTOR inhibitors such as everolimus is a new target agent for therapy that attempts to enhance treatment efficacy and restore tumor sensitivity. In this review article, we present the data about the use of everolimus for the treatment of breast cancer in all tumor phenotypes. Future studies that evaluate biomarkers for treatment response are needed to identify the specific populations that have the highest benefit of this new targeted therapy.
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