The increasing number of publications and new diagnostics (e.g., MammaTyper®, OncotypeDX® test, Xpert® Breast Cancer STRAT4) on the successful implementation of HER2 determination by molecular biology methods speaks more and more in favor of the idea that it is not the inherent limitations of the method but its good standardization that is important for its complementary use as a third alternative. Here, ERBB2 is linked to breast cancer.