Evaluation of HER2/neu status by immunohistochemistry using computer-based image analysis and correlation with gene amplification by fluorescence in situ hybridization assay: A 10-year experience and impact of test standardization on concordance rate

Venetia R. Sarode, Qun Diane Xiang, Alana Christie, Rebecca Collins, Roshni Rao, A. Marilyn Leitch, David Euhus, Barbara Haley

Research output: Contribution to journalArticle

Abstract

Context.- The American Society of Clinical Oncology/College of American Pathologists proposed several recommendations for human epidermal growth factor receptor 2 (HER2) test standardization. One suggestion was that image analysis (IA) could be useful for scoring of HER2/neu immunohistochemistry. The utilization of IA in a realworld practice in a large cohort of cases has not been previously reported. Objectives.- To compare HER2/neu quantification by IA with gene amplification by fluorescence in situ hybridization (FISH); to determine sensitivity, specificity, and concordance rates with the FISH assay; and to determine association between HER2 status with estrogen receptor (ER), progesterone receptor (PR), and Ki-67 expression. Design.- We evaluated HER2 results performed by immunohistochemistry and FISH in conjunction with ER, PR, and Ki-67 in 3093 invasive breast cancer cases from 2002 to 2011. Results.- The overall concordance between immunohistochemistry and FISH was 87.3% (1768 of 2026). When analyzed by year, there was an improvement in the positive concordance rate from 49.4% (44 of 89) to 95.0% (57 of 60) (P < .001). The negative concordance rate was at least 95% with a median false-negative rate of 1.5%. In the FISH+ group, amplification ratio showed significant correlation with IA scores (P < .001). Positive versus negative HER2 status was associated with lower ER and PR levels (P < .001) and higher Ki-67 expression (P < .001). Conclusion.- Scoring of HER2/neu by IA was associated with high false-positive rates before 2008. Improvement in concordance rate after 2008 may be due to proper tissue handling, improved HER2/neu scoring by IA, and assay standardization.

Original languageEnglish (US)
Pages (from-to)922-928
Number of pages7
JournalArchives of Pathology and Laboratory Medicine
Volume139
Issue number7
DOIs
StatePublished - Jul 1 2015
Externally publishedYes

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ASJC Scopus subject areas

  • Pathology and Forensic Medicine
  • Medical Laboratory Technology

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