ERBB2 and breast cancer: Two patients were negative for HER2 by immunohistochemistry IHC (with no FISH fluorescence or chromogenic in situ hybridization or CISH test) before the start of first-line therapy with P+T, and it remains unclear, why they received adjuvant treatment with T. However, at the time of inclusion into this NIS both patients had documented HER2+ BC, one by IHC (+++) and the other one by FISH.