title: Evaluation of Her-2/neu in Breast Cancer: Comparison of Immunohistochemistry and Polymerase Chain Reaction.
abstract: OBJECTIVE
  In breast cancer, Her-2/neu amplification/overexpression predicts a poor clinical outcome, and enhanced survival benefits have been reported with Her-2/neu targeted therapy. Currently, there are several methods for assessing the amplification/overexpression of Her-2/neu, each having advantages and disadvantages. The aim of this work was to establish a reproducible, sensitive and specific method of testing for Her-2/neu, which could be used in diagnostic pathology laboratories.
  
  
  METHODS
  We compared the immunohistochemistry (IHC) detection of Her-2/neu overexpression, with differential polymerase chain reaction (PCR) to assess the gene amplification of the Her-2/ neu, in 163 cases of invasive ductal carcinoma of the breast using paraffin-embedded tissue. In addition, assessment of the appropriate cut off points was established.
  
  
  RESULTS
  The overexpression of the Her-2/neu was detected in 39 (23.9%) cases, and its amplification in 37 (22.7%) cases. The methods were positive in 21.5% of cases and negative in 74.8%. There was a 96.3% concordance between the two methods. The sensitivity and specificity of IHC, compared with PCR, were 94.6 and 96.8%, respectively.
  
  
  CONCLUSIONS
  We conclude that the automation of PCR-based Her-2/neu testing approaches is expected to play an increasing role in the future of Her-2/neu testing. Also, we have demonstrated that IHC is a sensitive and specific method for assessing Her-2/neu stati in breast cancer, compared to PCR. The current study indicates that moderate, or strong, complete membrane staining in> or =10% of tumor cells provides an appropriate cut off point compared with PCR.
authors.forename: Mi Ja
authors.initials: MJ
authors.lastname: Lee
authors.forename: Ho Jong
authors.initials: HJ
authors.lastname: Jeon
keywords: Breast neoplasm; Her-2/neu; Immunohistochemistry; PCR