Classification into five molecular subtypes (Luminal A-like, Luminal B/HER2 negative-like, Luminal B/HER2 positive-like, HER2-type, Triple negative) helps to sort patients into groups with divergent prognoses and different response patterns to specific Every-day-routine outcome assessment of specialized breast cancer unit (BCU) must validate guideline-based care of BC patients in order to optimize the therapy of every individual case. The gene discussed is ERBB2; the disease is breast cancer.