%0 Journal Article
%T Comparison of Fluorescence In Situ Hybridization and Chromogenic In Situ Hybridization for Low and High Throughput HER2 Genetic Testing
%A Tim S. Poulsen
%A Maiken L. M. Espersen
%A Vibeke Kofoed
%A Tanja Dabetic
%A Estrid H£żgdall
%A Eva Balslev
%J International Journal of Breast Cancer
%D 2013
%I Hindawi Publishing Corporation
%R 10.1155/2013/368731
%X The purpose was to evaluate and compare 5 different HER2 genetic assays with different characteristics that could affect the performance to analyze the human epidermal growth factor 2 (HER2) gene copy number under low and high throughput conditions. The study included 108 tissue samples from breast cancer patients with HER2 immunohistochemistry (IHC) results scored as 0/1+, 2+, and 3+. HER2 genetic status was analysed using chromogenic in situ hybridization (CISH) and fluorescence in situ hybridization (FISH). Scoring results were documented through digital image analysis. The cancer region of interest was identified from a serial H&E stained slide following tissue cores were transferred to a tissue microarrays (TMA). When using TMA in a routine flow, all patients will be tested for HER2 status with IHC followed by CISH or FISH, thereby providing individual HER2 results. In conclusion, our results show that the differences between the HER2 genetic assays do not have an effect on the analytic performance and the CISH technology is superior to high throughput HER2 genetic testing due to scanning speed, while the IQ-FISH may still be a choice for fast low throughput HER2 genetic testing. 1. Introduction Human Epidermal growth factor Receptor 2 (HER2) expression is investigated routinely on all breast cancer cases to make the therapeutic decisions for patients with breast cancer. The American Society of Clinical Oncology (ASCO)/College of American Pathologist (CAP) recommendations for HER2 status testing are first immunohistochemical (IHC) staining and secondary to perform genetic HER2 testing on tissues scored as borderline cases (2+) found by IHC [1]. Ratio-based dual color HER2 gene amplification assays are commercially available from a multiple vendors using either fluorescence in situ hybridization (FISH) or chromogenic in situ hybridization (CISH), where the various tests have differing characteristics (Table 1). The HER2/neu labeled part of the dual color HER2 genetic assays is in all cases DNA based, while the centromere reference part can either be an DNA probe or an peptide nucleic acids (PNA) probe. The direct labeling of the different FISH probes from Dako and ZytoVision uses red (TexasRed), orange (Rhodamine), or green (FITC) fluorocrome, while the CISH-based assays give rise to either red, green, or blue chromogenic precipitation. Various strategies for blocking of nonspecific probe binding and detection systems have been implemented into the different HER2 genetic assays. ZytoVison uses repeat-free oligonucleotides and thereby does not need
%U http://www.hindawi.com/journals/ijbc/2013/368731/