[HER-2 oncogene amplification assessment in invasive breast cancer by dual-color in situ hybridization (dc-CISH): a comparative study with fluorescent in situ hybridization (FISH)]

Ann Pathol. 2011 Dec;31(6):472-9. doi: 10.1016/j.annpat.2011.10.013. Epub 2011 Nov 26.
[Article in French]


Objectives: The amplification of the gene encoding for the human epidermal growth factor receptor 2 (HER-2 oncogene), located on chromosome 17 (17q21-q22), or the overexpression of this receptor have prognostic and therapeutic implications in invasive breast cancer. An evaluation of the HER-2 status by immunohistochemistry (IHC) is performed on all invasive breast cancer cases. Fluorescent in situ hybridization (FISH) is considered as the gold standard for the detection of HER-2 gene amplification for IHC equivocal cases (score 2+). A more recent in situ hybridization technique, the dual-color chromogenic in situ hybridization (dc-CISH), has been proposed as an alternative to FISH. The aim of this study was to measure the correlation between dc-CISH and FISH for HER-2 oncogene amplification assessment in invasive breast cancer.

Methods and results: We built four tissue micro-array (TMA) blocs with 100 breast invasive cancer cases that had been previously tested by IHC for HER-2 detection: 10 score 0 cases, 10 score 3+cases, 39 score 1+and 41 score 2+cases. Both FISH and dc-CISH techniques were applied on all TMA cases as well as on two additional slides serving as controls. Interpretation of dc-CISH was carried out by a pathologist using an optical microscope. For FISH, the interpretation was done by a professional from the medical genetics department using a fluorescent microscope linked to a computer system for image capturing and analysis. The interpretation of the HER-2/CEN-17 ratio for both tests was in accordance with the values of the updated recommendations from the Canadian National Consensus Meeting on HER-2/neu testing in breast cancer and from the ASCO/CAP. Among the 100 cases initially included in the study, eight were excluded from the analysis due to sampling or technical flaws. From the 92 remaining cases, we obtained a concordance of 97.8% (90/92 cases) between the two techniques (Kappa coefficient 0.97, 95% confidence interval). The correlation coefficient (rho) between ratios was estimated at 0.57.

Conclusion: This study shows a strong concordance between FISH and dc-CISH techniques and indicates that dc-CISH is a good alternative method for HER-2 gene amplification assessment in breast cancer.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Review
  • Validation Study

MeSH terms

  • Breast Neoplasms / genetics*
  • Breast Neoplasms / pathology
  • Carcinoma, Ductal, Breast / genetics*
  • Carcinoma, Ductal, Breast / pathology
  • Carcinoma, Lobular / genetics
  • Carcinoma, Lobular / pathology
  • Chromosomes, Human, Pair 17 / genetics
  • Chromosomes, Human, Pair 17 / ultrastructure
  • Female
  • Fluorescent Dyes
  • Gene Amplification
  • Genes, erbB-2*
  • Humans
  • Image Interpretation, Computer-Assisted
  • Image Processing, Computer-Assisted
  • In Situ Hybridization / methods*
  • In Situ Hybridization, Fluorescence
  • Microscopy, Fluorescence
  • Neoplasm Invasiveness
  • Reproducibility of Results
  • Staining and Labeling


  • Fluorescent Dyes