Abstract:Objective To investigate the relationship between expressions of ER, PR, HER-2 and Ki-67 and the effective rate of neoadjuvant chemotherapy of breast cancer, and to investigate the predictive index on neoadjuvant chemotherapy for breast cancer. Methods Expressions of ER, PR, HER-2 and Ki-67 in breast cancer of 81 patients received neoadjuvant chemotherapy were detected by immunohistochemical method before and after chemotherapy. The relationships of expression levels and the effective rate were evaluated. Results The clinical RR in 81 patients was 79%, pCR after surgery was 9.9%, tpCR was 6.2%. Achieved PCR+tPCR rate, (ER-negative) 23.0% > (ER-positive) 12.7%, and (PR-negative) 28.6% > (PR-positive) 9.4%. There was no statistical difference between ER, PR, HER-2 and Ki67 with neoadjuvant chemotherapy. ER, PR, HER-2 negative or positive changes were not obvious for neoadjuvant chemotherapy, and the difference was not statistically significant (P > 0.05), while the number of Ki67 expression was statistically significant (P < 0.05), which reduced the expression levels of Ki67. Conclusions Neoadjuvant chemotherapy can effectively control the tumor. ER - or PR - negative receive a high errate of pCR + tPCR comparing with those positive. Ki67 may be a predictor for chemotherapy drug sensitivity and resistance.