title: Everolimus  in the treatment of hormone receptor-positive breast cancer.
abstract: BACKGROUND
  The phosphoinositide triphosphate kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) is a central regulatory pathway involved in cell proliferation, growth, differentiation, metabolism and survival. Deregulation of this pathway is well described in breast cancer and is associated to the development of endocrine resistance among hormone receptor (HR)-positive tumors. Everolimus , an mTOR-inhibitor has clinical activity against breast cancer and has shown to restore sensitivity to endocrine therapy.
  
  
  METHODS
  We review the clinical data and the results of the recently published clinical trials evaluating the use of everolimus in HR-positive breast cancer patients in combination with endocrine therapy. We discuss the data regarding efficacy but also describe in detail the side effect profile of this drug.
  
  
  CONCLUSIONS
  Everolimus represents a new therapeutic alternative for the treatment of HR-positive metastatic breast cancer. Everolimus is in general a well-tolerated drug, however, stomatitis, fatigue and hematological abnormalities are common. It is still unclear if there are specific subgroups of patients that receive greater benefit from everolimus and whether there is a relationship between the presence of PIK3CA mutations and efficacy. The results of biomarker studies will hopefully provide information that will help us determine which patients are most likely to benefit from this treatment.
authors.affiliation: The University of Texas, MD Anderson Cancer Center, Department of Breast Medical Oncology, 1155 Herman P Pressler, CPB5.3540, Houston, TX 77030, USA.
authors.forename: Mariana
authors.initials: M
authors.lastname: Chavez-MacGregor
authors.forename: Ana Maria
authors.initials: AM
authors.lastname: Gonzalez-Angulo
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology / Q000627:therapeutic use*; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000378:metabolism; D000068338:Everolimus; D006801:Humans; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D011987:Receptors, Steroid; D020123:Sirolimus / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000627:therapeutic use; D058570:TOR Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism
chemical_list: D000970:Antineoplastic Agents; D000068338:Everolimus; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt; D011987:Receptors, Steroid; D020123:Sirolimus; D058570:TOR Serine-Threonine Kinases; C546842:MTOR protein, human