MKI67 and breast carcinoma: In a phase 3 study comparing NET and neoadjuvant chemotherapy (NACT) for pre-menopausal patients with estrogen receptor-positive (ER+) N+ breast cancer, NET demonstrated a lower clinical response (53 % vs 84 %), as well as a lower nodal pathologic complete response (pCR) (4.9 % vs 13.8 %) than NACT.15 However, BCS conversion rates and change in Ki-67 expression did not differ significantly between the two groups.