The scoring of HER2 protein immunohistochemical expression patterns in breast cancer patients is a well-established protocol with commercially available validated antibodies (e.g. HercepTest, DAKO), Similar staining intensities and patterns of HER2 localization in tumor cells were obtained using the directly labelled anti-HER2 IgG, compared to those obtained using the conventional IHC method (Supplementary Figure S1A). This evidence concerns the gene ERBB2 and breast cancer.