Research Article

Immunohistochemical Antibodies in Breast Cancer HER2 Diagnostics
A Comparative Immunohistochemical and Fluorescence in situ Hybridization Study
Kristof Egervari, Zoltan Szollosi, Zoltan Nemes

Department of Pathology, Medical and Health Science Center, University of Debrecen, Debrecen, Hungary

Address of Corresponding Author

Tumor Biol 2008;29:18-27 (DOI: 10.1159/000132567)

  Key Words

• Breast cancer
• HER2
• Immunohistochemistry
• Fluorescence in situ hybridization
• Tissue microarray

  Abstract

Overexpression and/or gene amplification of the HER2 oncogene predicts worse prognosis and altered sensitivity to chemotherapy. Trastuzumab is capable of improving prognosis of HER2-positive breast cancer, but for the success of treatment appropriate HER2 testing is essential. Our aim was to determine the value of immunohistochemical (IHC) screening prior to fluorescence in situ hybridization (FISH). We assessed five conventional IHC assays (NCL-CB11, Pathway CB11, CBE356, CBE1, HercepTest) and the novel rabbit monoclonal antibody, RM-4B5, combined with FISH on 199 invasive breast cancer cases. Taking FISH as the endpoint, we calculated sensitivity, specificity, positive and negative predictive values (PPV, NPV) and accuracy for all IHC assays with either taking both 2+/3+ cases or only 3+ cases as IHC positives. With 2+/3+ cases HercepTest showed 100% sensitivity and NPV, while the highest specificity, PPV and accuracy was associated with RM-4B5 (97.36, 80 and 95.34%, respectively). The second highest values belonged to either NCL-CB11 or Pathway CB11. When calculating only with 3+ cases, the results were reversed with increased specificity, PPV and accuracy. Our findings suggest that improving sensitivity by using two parallel IHC reactions might be beneficial; we recommend primarily HercepTest and Pathway CB11. Nevertheless, we may consider performing FISH analysis without prior IHC screening.

Copyright © 2008 S. Karger AG, Basel

  Author Contacts

Zoltan Szollosi
Department of Pathology, Medical and Health Science Center
University of Debrecen, Nagyerdei krt. 98
HU-4012 Debrecen (Hungary)
Tel./Fax +36 52 417 063, E-Mail szollosi@jaguar.dote.hu

  Article Information

Received: September 6, 2007
Accepted after revision: January 14, 2008
Published online: May 23, 2008
Number of Print Pages : 10
Number of Figures : 1, Number of Tables : 3, Number of References : 47