title: Discordance in ERα, PR and HER2 receptor status across different distant breast cancer metastases within the same patient.
abstract: BACKGROUND
  We studied discordance in estrogen receptor alpha (ERα), progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER2) status between multiple distant metastases from the same breast cancer patient.
  
  
  METHODS
  Multiple distant metastases from 55 female patients were stained for ERα, PR and HER2 by immunohistochemistry and in situ hybridization for confirmation of the HER2 status.
  
  
  RESULTS
  Different metastatic sites within the same patient showed discordance in ERα receptor status in 7.3% or 10.9% of patients (using a 10% or 1% threshold for positivity, respectively). For PR, 29.1% or 30.9% of patients showed discordance. Taking ERα and PR together, 36.4% of cases (both thresholds) showed discrepancy between metastases. In 10.9% (10% threshold) or 14.5% of patients (1% threshold), such discordance could have clinical consequences with regard to hormonal treatment. For HER2, there was 3.6% discordance on the immunohistochemical level but 0% on the gene level.
  
  
  CONCLUSIONS
  In a significant proportion of metastatic breast cancer patients, discordance in ERα and PR receptor status between different metastatic sites was observed. This implies that multiple metastases may need to be biopsied to optimally reassess receptors.
authors.affiliation: Department of Pathology.
authors.forename: L D C
authors.initials: LD
authors.lastname: Hoefnagel
authors.forename: P
authors.initials: P
authors.lastname: van der Groep
authors.forename: M J
authors.initials: MJ
authors.lastname: van de Vijver
authors.forename: J E
authors.initials: JE
authors.lastname: Boers
authors.forename: P
authors.initials: P
authors.lastname: Wesseling
authors.forename: J
authors.initials: J
authors.lastname: Wesseling
authors.forename: E
authors.initials: E
authors.lastname: van der Wall
authors.forename: P J
authors.initials: PJ
authors.lastname: van Diest
mesh_terms: D001859:Bone Neoplasms / Q000378:metabolism* / Q000556:secondary; D001943:Breast Neoplasms / Q000378:metabolism* / Q000473:pathology; D018270:Carcinoma, Ductal, Breast / Q000378:metabolism* / Q000556:secondary; D047628:Estrogen Receptor alpha / Q000378:metabolism*; D005260:Female; D006801:Humans; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism*; D011980:Receptors, Progesterone / Q000378:metabolism*
chemical_list: D047628:Estrogen Receptor alpha; D018719:Erb-b2 Receptor Tyrosine Kinases; D011980:Receptors, Progesterone; C506487:ESR1 protein, human; C508053:ERBB2 protein, human
keywords: ERα; HER2; PR; breast cancer; immunohistochemistry; multiple metastases