Related Experiment Video
Updated: Dec 28, 2025
Validated Immunochemical Assay for Comprehensive Determination of the Human Epidermal Growth Factor Receptor 2 Released from and Bound to Cells
Published on: May 9, 2025
Re-evaluation of HER2 status in 606 breast cancers-gene protein assay on tissue microarrays versus routine
Emma Sandén1, Somayeh Khazaei1, Helga Tryggvadottir1
1Department of Clinical Sciences in Lund, Oncology and Pathology, Faculty of Medicine, Lund University Cancer Center / Kamprad, Lund University and Skåne University Hospital, Lund, Sweden.
Abstract:
Human epidermal growth factor receptor 2 (HER2) status in breast cancer is routinely determined through immunohistochemistry (IHC) and/or in situ hybridisation (ISH) performed on whole tissue sections (WS). The purpose was to evaluate whether a gene protein assay (GPA) combining IHC with ISH, performed on breast cancer tissue microarray (TMA), is suitable for large-scale retrospective HER2 status evaluation. TMAs from 606 tumours from a Swedish population-based cohort (2005-2012) were stained with GPA. GPA IHC on TMA yielded weaker staining than IHC on WS during routine pathological assessment (86.0% agreement). However, final HER2 status agreement between GPA on TMA and WS based on both IHC and ISH was 97.7%. Only 14 tumours were discordant and one tumour with IHC score 1+ on both TMA and WS was HER2 amplified on TMA. In conclusion, GPA on TMA is suitable for large-scale retrospective evaluation of HER2 status.
