Of those patients, 35 switched to 4 weeks of NCT because of Ki67>10% who experienced high a pCR rate of 5.7% and were more likely to undergo mastectomy and axillary lymph node dissection than those patients continuously received 4 weeks of NET, indicating that chemotherapy efficacy was lower than expected in HR-positive breast cancers resistant to NET. This evidence concerns the gene MKI67 and breast cancer.