...• Operable histologically confirmed breast cancer • Luminal B HER2-negative (ER positive, HER2 negative, and at least one of the following: Ki-67 ‘high’ (=20%) or PgR ‘negative or low’) or Luminal B HER2-positive (ER positive, HER2 over-expressed or amplified, any Ki-67, any PgR)• Early-stage (pT1-3; any nodal status) • Candidate to adjuvant chemotherapy and endocrine therapy• The tumor must be confined to the breast and axillary nodes without detected metastases elsewhere• Patients with synchronous (diagnosed histologically within 2 months) bilateral invasive breast cancer are eligible if all other criteria are met• Patients must have had surgery for primary breast cancer with no known clinical residual loco-regional disease• Margins must be negative for invasive breast cancer and DCIS• Patients should be start treatment as close to definitive surgery as possible (no later than 8 weeks)• No prior neoadjuvant or adjuvant therapy for breast cancer. ...