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Building Up a High-throughput Screening Platform to Assess the Heterogeneity of HER2 Gene Amplification in Breast Cancers
Published on: December 5, 2017
Concordance of HER2 Immunohistochemistry and Fluorescence In Situ Hybridization Using Tissue Microarray in Breast
Daniela Furrer1,2,3, Simon Jacob4,5,6, Chantal Caron4,5
1Cancer Research Center at Laval University, Faculty of Medicine, Laval University, Quebec City, Canada.
Aim:
Immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) are common methods for assessment of human epidermal growth factor receptor 2 (HER2) in breast cancer.
Materials And Methods:
In a cohort of 498 consecutive patients with breast cancer, we examined concordance between IHC and FISH for HER2 on tissue microarray (TMA) sections. In a subset of 116 specimens, we examined HER2 concordance from the block used for diagnostics and a randomly-chosen additional block (a proxy of the core biopsy).
Results:
Overall concordance between both methods on TMA sections was 93.8% and between HER2, determined on diagnostic and additional blocks, was 93.6% for IHC and 98.0% for FISH.
Conclusion:
Since some cases were discordant, we suggest that both methods be used for HER2 assessment. The lower concordance rate between diagnostic and additional blocks using IHC compared to FISH suggests a greater variability of IHC staining across tumor regions than for FISH results.
