4. Centrally confirmed negative HER2-status. Centrally confirmed estrogen and progesterone receptor, and Ki-67 status detected on core biopsy. ER/PR positive is defined as ≥1% stained cells and HER2-positive is defined as IHC 3+ or in-situ hybridisation (ISH) ratio ≥2.0. Formalin-fixed, paraffin-embedded (FFPE) breast tissue from core biopsy has therefore to be sent to the Dept. of Pathology at the Charité, Berlin prior to randomization.