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Effect of neoadjuvant chemotherapy on expressions of estrogen receptor, progesterone receptor, human epidermal growth factor receptor 2, and Ki‐67 in breast cancer

Background This study was designed in an attempt to determine the influence of neoadjuvant chemotherapy on estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (Her‐2), and Ki‐67 expressions in patients with breast cancer. Methods Pre‐ and post‐neoadjuvant chemotherapy, paired‐tumor specimens from 103 patients with breast cancer administrated with anthracycline or anthracycline combined taxane regimen were collected. Immunohistochemical staining for ER, PR, Her‐2, and Ki‐67 was performed by the DAKO EnVision method. Results Among the 103 cases, five patients (4.9%) had a complete response (CR), 82 (79.6%) partial response (PR), 15 (14.6%) stable disease (SD), and one (0.9%) progressive disease (PD), yielding an overall response rate (CR + PR) of 84.5%. Nine patients achieved pathological CR. There was a significant decrease in the average index of Ki‐67 post‐neoadjuvant chemotherapy, compared with that before chemotherapy (24.1% vs. 39.7%, P <0.001). After neoadjuvant chemotherapy, the changes of Ki‐67 in different subtypes of breast cancer were different (P <0.001), and these changes correlated with response to neoadjuvant chemotherapy (P <0.001). No significant changes in immunohistochemical expression were observed for ER, PR and Her‐2. Conclusions Neoadjuvant chemotherapy apparently reduced Ki‐67 index in primary breast carcinomas, but profiles for ER, PR and Her‐2 were not significantly different before and after neoadjuvant chemotherapy. The change of Ki‐67 correlated with molecular subtypes and response to neoadjuvant chemotherapy, suggesting that Ki‐67 index was a surrogate marker to predict the treatment response of neoadjuvant chemotherapy.