MKI67 and sarcomatoid carcinoma: The mFU of 39 months, 26 patients (27%) recurred (24 distant and 2 loco-regional). The OS rate of the cohort was 66% (64/97).5 (17%) showed a pCR. Of these 5 cases, 3 were pure matrix producing, 1 mixed matrix-producing and no special type, and 1 pure spindle cell carcinoma. All tumors resulting in pCR were ER/PrR negative, one was HER2+ and received targeted neoadj regimen, and all five showed a high Ki-67 labeling index (50% or higher).