Dual-color dual-hapten in situ hybridization (D-DISH) – Comparison with fluorescence in situ hybridization (FISH) for HER2/neu testing in breast cancer

Content Provider	Scilit
Author	Shet, Tanuja M. Gajaria, Pooja K. Pai, Trupti Patil, Asawari Desai, Sangeeta B. Tambe, Sonali
Copyright Year	2020
Abstract	Context: HER2/neu testing in breast cancer is a mandate due to availability of trastuzumab, a monoclonal antibody targeted against this biomarker. Dual-color dual-hapten in situ hybridization (D-DISH) is a new test for assessment of HER2/neu gene overexpression on light microscopy. Aims: This was a validation study for D-DISH in our laboratory and was conducted to study the concordance between fluorescence in situ hybridization (FISH) and D-DISH for HER2/neu testing in breast cancer. Materials and Methods: In all, 150 cases of invasive breast carcinoma requested for FISH analysis were selected. Immunohistochemistry by Ventana PATHWAY anti-HER2/neu (4B5) antibody, FISH by ZytoLight SPEC ERBB2/CEN17 Dual Color Probe, and D-DISH using the Ventana INFORM HER2 Dual ISH DNA Probe Cocktail Assay was carried out. Statistical Analysis: Cohen's kappa coefficient was used to calculate concordance between FISH and D-DISH assays. The ratios and average number of signals were compared with Lin's concordance correlation coefficient. Results: About 93.1% of the cases showed concordance between FISH and D-DISH results. Cohen's kappa correlation coefficient was 0.836, indicating almost perfect level of agreement. Lin's concordance correlation coefficient (ρc) showed moderate strength of agreement for HER2/chromosome 17 ratios between FISH and D-DISH assays (ρc 0.9452). As per the American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP) 2018 updated guidelines, four of the cases that were nonamplified on FISH showed low-level amplification on D-DISH due to counting errors caused by faint signals or background dust. Genomic heterogeneity and larger red chromosome 17 signals on D-DISH led to discordance of the six cases amplified by FISH. D-DISH failure rate was 3.33%. Conclusion: Overall, D-DISH showed good concordance with FISH but needs expertise for reporting.
Related Links	https://www.ijpmonline.org/article.asp?issn=0377-4929;year=2020;volume=63;issue=2;spage=194;epage=199;aulast=Gajaria;type=2
Ending Page	199
Page Count	6
Starting Page	194
File Format	XHTML
ISSN	03774929
e-ISSN	19362625
DOI	10.4103/IJPM.IJPM_861_19
Journal	Indian Journal of Pathology and Microbiology
Issue Number	2
Volume Number	63
Language	English
Publisher	Medknow
Publisher Date	2020-01-01
Access Restriction	Open
Subject Keyword	Medical Laboratory Technology Concordance Dual-color Dual-hapten in Situ Hybridization Fluorescence in Situ Hybridization Invasive Breast Carcinoma Validation Indian Journal of Pathology and Microbiology, Volume 63, Issue 2
Content Type	Text
Resource Type	Article
Subject	Pathology and Forensic Medicine Microbiology (medical)