title: The effect of delay in fixation on HER2 expression in invasive carcinoma of the breast assessed with immunohistochemistry and in situ hybridisation.
abstract: OBJECTIVE
  Accurate assessment of HER2 status is essential for selection of patients for HER2-targeted treatment such as trastuzumab. This study investigated the hypothesis that delayed fixation impairs HER2 assessment.
  
  
  METHODS
  9 carcinomas were received fresh, and samples were fixed immediately or put in fixative at time intervals up to 24 h. All carcinomas were scored as 3+ with immunohistochemistry in properly fixed tissue.
  
  
  RESULTS
  2 of 9 carcinomas (95% CIs 6% to 56%) showed reduced immunohistochemical staining with delays in fixation of 1 and 8 h. One carcinoma showed low-level amplification with fluorescence in situ hybridisation (FISH) when properly fixed and was not amplified after delayed fixation. The other carcinomas were amplified at all time points.
  
  
  CONCLUSIONS
  Delayed fixation impaired HER2 protein expression assessed using immunohistochemistry in 22% of 3+ carcinomas. HER2 amplification assessed using FISH may be less affected.
authors.affiliation: Department of Histopathology, Nottingham University Hospitals, City Hospital Campus, Nottingham, UK.
authors.forename: Andrew H S
authors.initials: AH
authors.lastname: Lee
authors.affiliation: Department of Histopathology, Nottingham University Hospitals, City Hospital Campus, Nottingham, UK.
authors.forename: Heather P
authors.initials: HP
authors.lastname: Key
authors.affiliation: Source Bioscience plc, Nottingham Business Park, Nottingham, UK.
authors.forename: Jane A
authors.initials: JA
authors.lastname: Bell
authors.affiliation: Department of Histopathology, Nottingham University Hospitals, City Hospital Campus, Nottingham, UK.
authors.forename: Patrick
authors.initials: P
authors.lastname: Kumah
authors.affiliation: Department of Histopathology, Nottingham University Hospitals, City Hospital Campus, Nottingham, UK.
authors.forename: Zsolt
authors.initials: Z
authors.lastname: Hodi
authors.affiliation: Department of Histopathology, Nottingham University Hospitals, City Hospital Campus, Nottingham, UK.
authors.forename: Ian O
authors.initials: IO
authors.lastname: Ellis
mesh_terms: D014408:Biomarkers, Tumor / Q000032:analysis / Q000235:genetics; D001943:Breast Neoplasms / Q000201:enzymology* / Q000235:genetics* / Q000473:pathology; D002277:Carcinoma / Q000201:enzymology* / Q000235:genetics* / Q000473:pathology; D005260:Female; D005784:Gene Amplification; D006801:Humans; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence; D009361:Neoplasm Invasiveness; D011237:Predictive Value of Tests; D011379:Prognosis; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000032:analysis / Q000235:genetics; D015203:Reproducibility of Results; D013048:Specimen Handling / Q000379:methods*; D013997:Time Factors; D016707:Tissue Fixation
chemical_list: D014408:Biomarkers, Tumor; D018719:Erb-b2 Receptor Tyrosine Kinases; C508053:ERBB2 protein, human
keywords: Breast; Fixation; Immunohistochemistry; In Situ Hybridisation