title: Automated quantitative analysis of estrogen receptor expression in breast carcinoma does not differ from expert pathologist scoring: a tissue microarray study of 3,484 cases.
abstract: BACKGROUND
  Estrogen receptor (ER) expression is routinely assessed by immunohistochemistry (IHC) in breast carcinoma. Our study compares visual scoring of ER in invasive breast cancer by histopathologists to quantitation of staining using a fully automated system.
  
  
  METHODS
  A tissue microarray was constructed from 4,049 cases (3,484 included in analysis) of invasive breast carcinoma linked to treatment and outcome information. Slides were scored independently by two pathologists and scores were dichotomised, with ER positivity recognized at a cut-off of >1% positive nuclei. The slides were scanned and analyzed with an Ariol automated system.
  
  
  RESULTS
  Using data dichotomised as ER positive or negative, both visual and automated scores were highly consistent: there was excellent concordance between two pathologists (kappa = 0.918 (95%CI: 0.903-0.932)) and between two Ariol machines (kappa = 0.913 (95%CI: 0.897-0.928)). The prognostic significance of ER positivity was similar whether determined by pathologist or automated scoring for both the entire patient cohort and subsets of patients treated with tamoxifen alone or receiving no systemic adjuvant therapy. The optimal cut point for the automated scores using breast cancer disease-specific survival as an endpoint was >0.4% positive nuclei. The concordance between dextran-coated charcoal ER biochemical assay data and automated scores (kappa = 0.728 (95%CI: 0.69-0.75); 0.74 (95%CI: 0.71-0.77)) was similar to the concordance between biochemical assay and pathologist scores (kappa = 0.72 (95%CI: 0.70-0.75; 0.70 (95%CI: 0.67-0.72)).
  
  
  CONCLUSIONS
  Fully automated quantitation of ER immunostaining yields results that do not differ from human scoring against both biochemical assay and patient outcome gold standards.
authors.affiliation: Genetic Pathology Evaluation Centre, Vancouver Coastal Health Research Institute, Vancouver, BC, Canada.
authors.forename: Dmitry A
authors.initials: DA
authors.lastname: Turbin
authors.forename: Samuel
authors.initials: S
authors.lastname: Leung
authors.forename: Maggie C U
authors.initials: MC
authors.lastname: Cheang
authors.forename: Hagen A
authors.initials: HA
authors.lastname: Kennecke
authors.forename: Kelli D
authors.initials: KD
authors.lastname: Montgomery
authors.forename: Steven
authors.initials: S
authors.lastname: McKinney
authors.forename: Diana O
authors.initials: DO
authors.lastname: Treaba
authors.forename: Niki
authors.initials: N
authors.lastname: Boyd
authors.forename: Lynn C
authors.initials: LC
authors.lastname: Goldstein
authors.forename: Sunil
authors.initials: S
authors.lastname: Badve
authors.forename: Allen M
authors.initials: AM
authors.lastname: Gown
authors.forename: Matt
authors.initials: M
authors.lastname: van de Rijn
authors.forename: Torsten O
authors.initials: TO
authors.lastname: Nielsen
authors.forename: C Blake
authors.initials: CB
authors.lastname: Gilks
authors.forename: David G
authors.initials: DG
authors.lastname: Huntsman
mesh_terms: D001943:Breast Neoplasms / Q000188:drug therapy / Q000378:metabolism* / Q000401:mortality; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D007150:Immunohistochemistry; D053208:Kaplan-Meier Estimate; D011960:Receptors, Estrogen / Q000096:biosynthesis*; D015203:Reproducibility of Results; D020845:Selective Estrogen Receptor Modulators / Q000627:therapeutic use; D013629:Tamoxifen / Q000627:therapeutic use; D046888:Tissue Array Analysis
chemical_list: D011960:Receptors, Estrogen; D020845:Selective Estrogen Receptor Modulators; D013629:Tamoxifen