International guidelines for scoring of immunohistohemical and in situ hybridisation signals are available and widely used in HER2 testing in breast cancer [1, 3–5] Practising pathologists, being involved in breast pathology diagnostic service, need special training and long term expertise in order to achieve reproducible and standardized HER2 test results using the international guidelines [2, 6, 7]. Here, ERBB2 is linked to breast cancer.