ESR1 and neoplasm: Previous research has established the predictability of pCR or downstaging tumors to enable BCS after NACT for patients with negative ER or PR status.28,29 Raphael et al. reported lower odds of tumor response and pCR at surgery with increasing ER percent positive among patients who receive NACT.18 The current study further depicts inverse associations between continuous ER and PR expression and BCS and a positive association between Ki-67 expression and BCS.