MKI67 and breast cancer: Other biomarkers have been investigated to predict pCR after preoperative therapy in patients with breast cancer.58 The use of Ki-67 to predict pCR is widely described in literature.58–60 A recent meta-analysis60 showed a statistically significant difference in pCR rates between high and low Ki-67 expression [odds ratio (OR) 2.94; 95% CI 2.20–3.93].