Neoadjuvant chemotherapy is an important treatment for breast cancer patients. Patients with triple negative or Her2 enriched subtype who achieved pCR after neoadjuvant chemotherapy would have longer survival. But the overall pCR rate of breast cancer was about 20%. So, different methods have tried to improve pCR rate.Drug sensitivity screening in vitro for different chemotherapy drugs was a promising method for improving pCR rate. But there was no method could select effective drugs accurately for breast cancer patients until now. This study will explore whether drug screening by culturing breast cancer cells in vitro from breast cancer tissue could improve pCR rate compared with traditional neoadjuvant chemotherapy. Breast cancer patients who were candidates for neoadjuvant chemotherapy will be allocated two group. One group will receive neoadjuvant cheotherapy according physician's choices. Another group will receive neoadjuvant chemotherapy according results of drug sensitivity results by in vitro cell culture. pCR rate will be compared between two groups to explore whether drug sensitivity screening could improve pCR rate.

Neoadjuvant chemotherapy for breast cancer could make unresectable breast cancer be resectable and improve breast conservation rate. Patients with triple negative or Her2 enriched subtype who achieved pCR after neoadjuvant chemotherapy would have better survival. But the overall pCR rate of breast cancer was about 20%. And patients with luminal like subtype were less reactive for neoadjuvant chemotherapy. Improving pCR rate maybe could achieve better survival. So, different methods have tried to improve pCR rate.Drug sensitivity screening in vitro for different chemotherapy drugs was a promising method for improving pCR rate. But there was no method could select effective drugs accurately until now. This study will explore whether drug screening by culturing breast cancer cells in vitro from breast cancer tissue could improve pCR rate compared with neoadjuvant chemotherapy depend on physician's choice. 200 breast cancer patients who were candidates for neoadjuvant chemotherapy will be allocated to two group. One group with 100 patients will receive neoadjuvant cheotherapy according physician's choices. Another group with 100 patients will receive neoadjuvant chemotherapy according results of drug sensitivity results by in vitro cell culture. pCR rate will be compared between two groups to explore whether drug sensitivity screening could improve pCR rate.

Inclusion Criteria:

• invasive breast cancer candidate for neoadjuvant chemotherapy normal liver and renal function agreed to participate in this experiment

Exclusion Criteria:

• inflammatory breast cancer patients can not receive operation after neoadjuvant chemotherapy distant metastasis