title: Improved Risk Stratification for Breast Cancer Samples Based on the Expression Ratio of the Estrogen and Progesterone Receptor.
abstract: BACKGROUND
  The receptors for estrogen (ESR1) and progesterone (PGR) are both part of the same signaling pathway and routinely used for breast cancer stratification. We tested the hypothesis if a coordinated analysis could add extra information for prognostic stratification.
  
  
  METHODS
  ESR1 and PGR gene expression was first investigated by quantitative reverse transcription polymerase chain reaction in fresh-frozen invasive ductal breast cancer samples (Hamburg collective, case-control, n=317). Our results were then tested using two datasets generated by different technical approaches: i) a public DNA-chip data set (GSE3494, n=251) and ii) semiquantitative protein expression data based on immunohistochemistry (Stuttgart collective, n=18,528).
  
  
  RESULTS
  The PGR/ESR1 gene-expression ratio was a prognostic indicator in those with ESR1/PGR-positive breast cancer (Hamburg collective), with a high PGR/ESR1 expression ratio indicating a favorable outcome. In all three collectives, the PGR/ESR1 mRNA ratio or its protein equivalent was a univariate prognostic factor and also a multivariate prognostic factor in the Hamburg and Stuttgart collectives.
  
  
  CONCLUSIONS
  Calculation of the PGR/ESR1 gene-expression ratio and its immunohistochemical surrogate could be a useful and simple addition to routine breast cancer diagnostics. A high PGR/ESR1 ratio could be indicative of a favorable clinical outcome.
authors.affiliation: Institute for Molecular Cell Biology, University Hospital Hamburg-Eppendorf, Hamburg, Germany Pathology Hamburg-West, Hamburg, Germany.
authors.forename: Klaus
authors.initials: K
authors.lastname: Bendrat
authors.affiliation: Oncological Center Stuttgart e.V., Stuttgart, Germany Institute for Pathology, Robert Bosch Hospital Stuttgart, Stuttgart, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Fritz
authors.affiliation: MUON-STAT, Statistical Consulting, Stuttgart, Germany.
authors.forename: Simon
authors.initials: S
authors.lastname: Müller
authors.affiliation: Pathology Hamburg-West, Hamburg, Germany.
authors.forename: Sylvia
authors.initials: S
authors.lastname: Brockmöller
authors.affiliation: Pathology Hamburg-West, Hamburg, Germany.
authors.forename: Annegret
authors.initials: A
authors.lastname: Debus
authors.affiliation: Breast Center Hamburg, Jerusalem Hospital, Hamburg, Germany.
authors.forename: Kay
authors.initials: K
authors.lastname: Friedrichs
authors.affiliation: Diakonie-Hospital Hamburg gGmbH, Hamburg, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Lindner
authors.affiliation: Oncological Center Stuttgart e.V., Stuttgart, Germany.
authors.forename: Friedhelm
authors.initials: F
authors.lastname: Brinkmann
authors.affiliation: Oncological Center Stuttgart e.V., Stuttgart, Germany.
authors.forename: Else
authors.initials: E
authors.lastname: Heidemann
authors.affiliation: Pathology Hamburg-West, Hamburg, Germany a.niendorf@pathologie-hh-west.de.
authors.forename: Axel
authors.initials: A
authors.lastname: Niendorf
mesh_terms: D000368:Aged; D014408:Biomarkers, Tumor / Q000096:biosynthesis* / Q000235:genetics; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000235:genetics* / Q000473:pathology; D047628:Estrogen Receptor alpha / Q000096:biosynthesis* / Q000235:genetics; D004967:Estrogens / Q000235:genetics; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D053208:Kaplan-Meier Estimate; D008875:Middle Aged; D011379:Prognosis; D011980:Receptors, Progesterone / Q000096:biosynthesis* / Q000235:genetics; D018570:Risk Assessment
chemical_list: D014408:Biomarkers, Tumor; D047628:Estrogen Receptor alpha; D004967:Estrogens; D011980:Receptors, Progesterone
keywords: Estrogen receptor; IHC; PGR/ESR1 ratio; breast cancer; progesterone receptor; prognosis