title: Androgen receptor expression shows distinctive significance in ER positive and negative breast cancers.
abstract: BACKGROUND
  Androgen receptor (AR), a nuclear steroid hormone receptor, is differentially expressed in breast cancer subgroups with distinct clinical implications.
  
  
  METHODS
  To investigate the clinical significance of AR in breast cancers more precisely, the expression of AR in a large cohort of breast cancer was correlated with clinicopathological features, biomarker expression, and patients' survival according to different molecular groupings in this study.
  
  
  RESULTS
  Higher AR expression was found in ER+ (57.8 %) than in ER- (24.7 %) cancers. In the ER+ cancers, AR expression was associated with favorable clinicopathological features, including lower grade (p < .001), lower pT stage (p < .001), and positivity for PR (p < .001). It was an independent prognostic factor for longer disease-free survival, mainly in the HER2+ luminal B cancers (hazard ratio [HR] = 0.251, 95 % CI 0.065-0.972, p = .045). In ER- cancers, AR expression was associated with features distinct from basal-like breast cancer, and such features were found in molecular apocrine (MA) cancers. AR correlated with presence of extensive in situ component (p = .006) and apocrine phenotype (p < .001), HER2 (p = .026), and EGFR (p = .048), but negatively with c-kit (p = .041), CK5/6 (p < .001), CK14 (p = .002), and αB-crystallin (p = .038). However, AR expression was found only in 37.8 % of immunohistochemically defined MA. Of note, AR-MA appeared to have a trend of worse overall survival than AR+MA.
  
  
  CONCLUSIONS
  AR expression was different in ER+ and ER- cancers and had different clinical implications. AR alone may not be a good marker for MA subtype. Its expression in MA may have substantial prognostic implication and as such warrants further validation.
authors.affiliation: Department of Anatomical and Cellular Pathology, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong, China.
authors.forename: Julia Y S
authors.initials: JY
authors.lastname: Tsang
authors.forename: Yun-Bi
authors.initials: YB
authors.lastname: Ni
authors.forename: Siu-Ki
authors.initials: SK
authors.lastname: Chan
authors.forename: Mu-Min
authors.initials: MM
authors.lastname: Shao
authors.forename: Bonita K B
authors.initials: BK
authors.lastname: Law
authors.forename: Puay Hoon
authors.initials: PH
authors.lastname: Tan
authors.forename: Gary M
authors.initials: GM
authors.lastname: Tse
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000378:metabolism*; D001943:Breast Neoplasms / Q000378:metabolism* / Q000401:mortality / Q000473:pathology; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007124:Immunoenzyme Techniques; D008875:Middle Aged; D060787:Neoplasm Grading; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D011379:Prognosis; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism; D011944:Receptors, Androgen / Q000378:metabolism*; D011960:Receptors, Estrogen / Q000378:metabolism*; D011980:Receptors, Progesterone / Q000378:metabolism; D015996:Survival Rate; D046888:Tissue Array Analysis; D055815:Young Adult
chemical_list: D014408:Biomarkers, Tumor; D018719:Erb-b2 Receptor Tyrosine Kinases; D011944:Receptors, Androgen; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; C410798:AR protein, human