[Evaluation of Pre-Therapeutic Ki-67 as a Predictive Marker for Histological Response to Neoadjuvant Therapy in Breast Cancer].

ABSTRACT

There is controversy as to whether the proliferative marker Ki-67 is useful as a predictive marker for response to neoadjuvant therapy in breast cancer. We evaluated Ki-67 levels in pre-therapeutic breast cancer core biopsies from 52 breast cancer patients. These patients underwent anthracycline and taxane-based chemotherapy (n=48) or endocrine therapy (n=4) followed by surgery between March 2010 and February 2015. Expression of estrogen receptor (ER), progesterone receptor (PgR), HER2, and Ki-67 were examined by immunohistochemistry in the core-needle biopsy specimens. Ki-67 levels were categorized into 3 groups low (<20%), intermediate (20-50%), and high (≥50%). Pathological response rates were 29%, 15%, and 48% in the low, intermediate, and high-risk groups, respectively. In univariate analysis, pre-therapeutic high levels of Ki-67, as well as negative ER status were significantly associated with the responder group (p<0.05). However, neither Ki- 67 nor ER status were significantly associated with a response in multivariate analysis. Ki-67 appears to be a promising parameter for histological response to neoadjuvant therapy in breast cancer.