title: Comparative study between quantitative digital image analysis and fluorescence in situ hybridization of breast cancer equivocal human epidermal growth factor receptors 2 score 2(+) cases.
abstract: BACKGROUND
  Optimization of workflow for breast cancer samples with equivocal human epidermal growth factor receptors 2 (HER2)/neu score 2(+) results in routine practice, remains to be a central focus of the on-going efforts to assess HER2 status. According to the College of American Pathologists/American Society of Clinical Oncology guidelines equivocal HER2/neu score 2(+) cases are subject for further testing, usually by fluorescence in situ hybridization (FISH) investigations. It still remains on open question, whether quantitative digital image analysis of HER2 immunohistochemistry (IHC) stained slides can assist in further refining the HER2 score 2(+).
  To assess utility of quantitative digital analysis of IHC stained slides and compare its performance to FISH in cases of breast cancer with equivocal HER2 score 2(+).
  
  
  METHODS
  Fifteen specimens (previously diagnosed as breast cancer and was evaluated as HER 2(-) score 2(+)) represented the study population. Contemporary new cuts were prepared for re-evaluation of HER2 immunohistochemical studies and FISH examination. All the cases were digitally scanned by iScan (Produced by BioImagene [Now Roche-Ventana]). The IHC signals of HER2 were measured using an automated image analyzing system (MECES, www.Diagnomx.eu/meces). Finally, a comparative study was done between the results of the FISH and the quantitative analysis of the virtual slides.
  
  
  RESULTS
  Three out of the 15 cases with equivocal HER2 score 2(+), turned out to be positive (3(+)) by quantitative digital analysis, and 12 were found to be negative in FISH too. Two of these three positive cases proved to be positive with FISH, and only one was negative.
  
  
  CONCLUSIONS
  Quantitative digital analysis is highly sensitive and relatively specific when compared to FISH in detecting HER2/neu overexpression. Therefore, it represents a potential reliable substitute for FISH in breast cancer cases, which desire further refinement of equivocal IHC results.
authors.affiliation: Department of Pathology, Faculty of Medicine, Cairo University, Cairo, Egypt.
authors.forename: Essam
authors.initials: E
authors.lastname: Ayad
authors.affiliation: Department of Pathology, Faculty of Medicine, Cairo University, Cairo, Egypt.
authors.forename: Mina
authors.initials: M
authors.lastname: Mansy
authors.affiliation: Department of Pathology, Faculty of Medicine, Cairo University, Cairo, Egypt.
authors.forename: Dalal
authors.initials: D
authors.lastname: Elwi
authors.affiliation: Department of Pathology, Faculty of Medicine, Cairo University, Cairo, Egypt.
authors.forename: Mostafa
authors.initials: M
authors.lastname: Salem
authors.affiliation: Department of Pathology, University of Utah and ARUP Reference Lab, Utah, USA.
authors.forename: Mohamed
authors.initials: M
authors.lastname: Salama
authors.affiliation: Department of Pathology, Humbold University Berlin, Berlin, Germany.
authors.forename: Klaus
authors.initials: K
authors.lastname: Kayser
keywords: Breast cancer; fluorescence in situ hybridization; human epidermal growth factor receptors 2; quantitative digital image analysis