Nowadays neoadjuvant chemotherapy (NAC) is the standard treatment for advanced breast cancer(BC) decreasing the extent of surgery.Many studies showed that the Ki67 proliferation marker could predict response to NAC. According to our results, high expression of Ki67 in biopsy and a decrease in surgical specimens suggests a sensibility to neoadjuvant chemotherapy.Our results suggest that tumors with Ki67 over 40% have better response to NAC, but we cannot state that Ki67 is a predictor of NAC, especially not for all intrinsic subtypes equally.