HER2 fluorescence in situ hybridization in amplified cases. A). Amplified case showing Homogeneously Staining Regions (HSR). HSR are large clusters of HER2 fluorescence signals indicating the presence of HER2 gene amplification in tandem repeats. B). Amplified case without HSR. HER2 signals are identifiable as single spots.
Furrer et al. Diagnostic Pathology 2013 8:17 doi:10.1186/1746-1596-8-17