title: Validation of EP1 Antibody Clone for Estrogen Receptor Immunohistochemistry for Breast Cancer.
abstract: BACKGROUND
  SP1 Rabbit monoclonal antibody to estrogen receptor (ER) has long been the standard for determination of ER status in breast cancer but has been replaced by the rabbit EP1 clone.
  
  
  OBJECTIVE
  To validate the EP1 antibody clone for use in determination of breast cancer ER status in a large clinical population against the previous standard SP1.
  
  
  METHODS
  ER immunohistochemistry was assessed in 523 consecutive cases from a clinical setting using tissue microarrays.
  
  
  RESULTS
  The kappa statistic showed that the agreement of ER status between SP1 and EP1 was considered to be almost perfect (kappa=0.97, 95% confidence interval=0.94-1.00). Sensitivity was 99.3%, specificity was 98.6% and overall agreement was 99.2%.
  
  
  CONCLUSIONS
  The EP1 antibody was herein validated regarding its use in breast cancer with almost perfect agreement with the previously used standard SP1 antibody.
authors.affiliation: Oncology Unit, Quebec University Hospital Research Center - Laval University, Quebec City, QC, Canada Deschênes-Fabia Breast Diseases Center, Quebec University Hospital Research Center - Laval University, Quebec City, QC, Canada Department of Preventive and Social Medicine, Laval University, Quebec City, QC, Canada caroline.diorio@crchudequebec.ulaval.ca.
authors.forename: Caroline
authors.initials: C
authors.lastname: Diorio
authors.affiliation: Oncology Unit, Quebec University Hospital Research Center - Laval University, Quebec City, QC, Canada Department of Preventive and Social Medicine, Laval University, Quebec City, QC, Canada.
authors.forename: Daniela
authors.initials: D
authors.lastname: Furrer
authors.affiliation: Oncology Unit, Quebec University Hospital Research Center - Laval University, Quebec City, QC, Canada.
authors.forename: Annick
authors.initials: A
authors.lastname: Michaud
authors.affiliation: Deschênes-Fabia Breast Diseases Center, Quebec University Hospital Research Center - Laval University, Quebec City, QC, Canada Pathology Department, Saint-Sacrement Hospital, Quebec University Hospital Research Center - Laval University, Quebec City, QC, Canada Department of Molecular Biology, Medical Biochemistry, and Pathology, Laval University, Quebec City, QC, Canada.
authors.forename: Sophie
authors.initials: S
authors.lastname: Laberge
authors.affiliation: Deschênes-Fabia Breast Diseases Center, Quebec University Hospital Research Center - Laval University, Quebec City, QC, Canada Pathology Department, Saint-Sacrement Hospital, Quebec University Hospital Research Center - Laval University, Quebec City, QC, Canada Department of Molecular Biology, Medical Biochemistry, and Pathology, Laval University, Quebec City, QC, Canada.
authors.forename: Ion
authors.initials: I
authors.lastname: Popa
authors.affiliation: Deschênes-Fabia Breast Diseases Center, Quebec University Hospital Research Center - Laval University, Quebec City, QC, Canada Pathology Department, Saint-Sacrement Hospital, Quebec University Hospital Research Center - Laval University, Quebec City, QC, Canada Department of Molecular Biology, Medical Biochemistry, and Pathology, Laval University, Quebec City, QC, Canada.
authors.forename: Simon
authors.initials: S
authors.lastname: Jacob
authors.affiliation: Oncology Unit, Quebec University Hospital Research Center - Laval University, Quebec City, QC, Canada Deschênes-Fabia Breast Diseases Center, Quebec University Hospital Research Center - Laval University, Quebec City, QC, Canada Department of Surgery, Laval University, Quebec City, QC, Canada.
authors.forename: Louise
authors.initials: L
authors.lastname: Provencher
authors.affiliation: Deschênes-Fabia Breast Diseases Center, Quebec University Hospital Research Center - Laval University, Quebec City, QC, Canada.
authors.forename: Jean-Charles
authors.initials: JC
authors.lastname: Hogue
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000378:metabolism*; D014408:Biomarkers, Tumor; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D011817:Rabbits; D011960:Receptors, Estrogen / Q000378:metabolism*; D058306:Receptors, Prostaglandin E, EP1 Subtype / Q000235:genetics / Q000378:metabolism*
chemical_list: D000911:Antibodies, Monoclonal; D014408:Biomarkers, Tumor; D011960:Receptors, Estrogen; D058306:Receptors, Prostaglandin E, EP1 Subtype
keywords: Estrogen receptor; antibody; breast cancer; immunohistochemistry