Bright-field HER2 dual in situ hybridization (DISH) assay vs fluorescence in situ hybridization (FISH): focused study of immunohistochemical 2+ cases.

Abstract

OBJECTIVES:

To compare the INFORM HER2 bright-field dual in situ hybridization (DISH) DNA probe cocktail assay with the PathVysion fluorescence in situ hybridization (FISH) assay on 103 invasive breast carcinomas with a 2+ score on immunohistochemistry (IHC).

METHODS:

The cases were categorized as positive, equivocal, or negative for HER2 gene amplification using the 2007 American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP) HER2:CEP17 ratio criteria and also based on mean HER2 gene copies/cell. The third criterion used a HER2:CEP17 ratio of 2 to categorize cases as positive or negative.

RESULTS:

The agreement between FISH and DISH was 85% using the 2007 ASCO/CAP ratio criterion, 79% using the mean HER2 gene copies/cell criterion, and 92% using the 2.0 cutoff HER2:CEP17 ratio criterion. In addition, 20 known IHC 3+ breast carcinomas analyzed by DISH showed clusters of the HER2 gene consistent with unequivocal amplification.

CONCLUSIONS:

Despite some technical and interpretational issues associated with DISH, it compares favorably with FISH in this group of challenging breast cancer cases.

• Authors: Faye F Gao, David J Dabbs, Kristine L Cooper, Rohit Bhargava
• Journal: American journal of clinical pathology (Am J Clin Pathol) Vol. 141 Issue 1 Pg. 102-10 (Jan 2014) ISSN: 1943-7722 [Electronic] England
• PMID: 24343743 (Publication Type: Comparative Study, Journal Article, Research Support, N.I.H., Extramural)

Chemical References

• Receptor, ErbB-2

Topics

• Breast Neoplasms (genetics, pathology)
• Chromosomes, Human, Pair 17 (ultrastructure)
• Female
• Genes, erbB-2
• Humans
• Immunohistochemistry
• In Situ Hybridization (methods)
• In Situ Hybridization, Fluorescence (methods)
• Receptor, ErbB-2 (biosynthesis)