title: Androgen receptor expression and outcomes in early breast cancer: a systematic review and meta-analysis.
abstract: BACKGROUND
  The androgen receptor (AR) is expressed frequently in breast cancer, but its prognostic significance is unclear. Preclinical data suggest that expression of AR may modify clinical outcomes in early breast cancer with improved prognosis in estrogen receptor (ER)-positive disease and poorer prognosis in ER-negative disease.
  
  
  METHODS
  A systematic review of electronic databases was conducted to identify studies published between 1946 and July 2012 and to explore the association between AR expression and overall survival (OS) and disease-free survival (DFS) in women diagnosed with early breast cancer. The odds ratios (OR) for OS and DFS at 3 and 5 years were calculated and then weighted and pooled in a meta-analysis with Mantel-Haenszel random-effect modeling. All statistical tests were two-sided.
  
  
  RESULTS
  Nineteen studies with a total of 7693 women were included. AR expression was documented in 60.5% of patients. ER-positive tumors were more likely to express AR- than ER-negative tumors (74.8% vs 31.8%, χ(2) P < .001). Compared with tumors without AR expression, those expressing AR were associated with improved OS at both 3 and 5 years (OR = 0.47, 95% confidence interval [CI] = 0.39 to 0.58, P < .001; and OR = 0.40, 95% CI = 0.29 to 0.56, P < .001). The absolute differences in the probability of OS at 3 and 5 years were 6.7% (95% CI = 3.5% to 9.8%) and 13.5% (95% CI = 7.5% to 19.6%), respectively. Results for 3- and 5-year DFS were similar. Coexpression of the ER did not influence OS at 3 or at 5 years.
  
  
  CONCLUSIONS
  Expression of AR in women with breast cancer is associated with better OS and DFS irrespective of coexpression of ER.
authors.affiliation: Affiliations of authors: Division of Medical Oncology & Hematology, Princess Margaret Cancer Centre, Department of Medicine, University of Toronto, Toronto, Canada (FEV-B, AJT, PdG, ID-P, PLB, MA-M, IFT, AO, EA); Sector of Medical Oncology, Institute of Oncology Ljubljana, Ljubljana, Slovenia (BS); Medical Oncology Department and Translational Research Unit, Albacete University Hospital, Albacete, Spain (AO).
authors.forename: Francisco E
authors.initials: FE
authors.lastname: Vera-Badillo
authors.forename: Arnoud J
authors.initials: AJ
authors.lastname: Templeton
authors.forename: Paulo
authors.initials: P
authors.lastname: de Gouveia
authors.forename: Ivan
authors.initials: I
authors.lastname: Diaz-Padilla
authors.forename: Philippe L
authors.initials: PL
authors.lastname: Bedard
authors.forename: Mustafa
authors.initials: M
authors.lastname: Al-Mubarak
authors.forename: Bostjan
authors.initials: B
authors.lastname: Seruga
authors.forename: Ian F
authors.initials: IF
authors.lastname: Tannock
authors.forename: Alberto
authors.initials: A
authors.lastname: Ocana
authors.forename: Eitan
authors.initials: E
authors.lastname: Amir
mesh_terms: D014408:Biomarkers, Tumor / Q000378:metabolism*; D001943:Breast Neoplasms / Q000378:metabolism* / Q000401:mortality* / Q000473:pathology / Q000628:therapy; D017024:Chemotherapy, Adjuvant; D016208:Databases, Factual; D018572:Disease-Free Survival; D055088:Early Detection of Cancer; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D053208:Kaplan-Meier Estimate; D019394:Ki-67 Antigen / Q000378:metabolism; D060787:Neoplasm Grading; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D016017:Odds Ratio; D011944:Receptors, Androgen / Q000378:metabolism*; D011960:Receptors, Estrogen / Q000378:metabolism
chemical_list: C410798:AR protein, human; D014408:Biomarkers, Tumor; D019394:Ki-67 Antigen; D011944:Receptors, Androgen; D011960:Receptors, Estrogen