Patients with breast cancer meet criteria for enrollment are randomized into PTC group or control group. The neoadjuvant therapy regimens are guided by PTC test in the PTC group. The regimens in control group are included of (dd)EC-T for HER2 negative subtype, TCH(P) or EC-TH(P) for HER2 positive subtype. We compared the pCR rate between two groups as the primary endpoint.

1. Before neoadjuvant therapy, all samples will be obtained by core needle biopsy for PTC drug sensitivity test.
2. After obtaining drug sensitivity results and confirming ER/PR and HER2 expression state, all recruited patients will be randomized into the PTC group or the routine treatment group, according to the method of random number table.
3. Beijing Cornerstone Life Science and Technology Co., Ltd. is responsible for gene sequencing and PTC drug sensitivity test for biological samples. All samples for the study are clinical residuals and will be used in the study, store or destruction is unapplicable.
4. Neoadjuvant therapy regimen in the PTC group is guided by PTC drug sensitivity results, and regimen in the routine treatment group is based on clinical guideline, such as (dd)EC-T for HER2 negative breast cancer, and TCH(P) or EC-TH(P) for HER2 positive breast cancer. All neoadjuvant therapy will be completed before operation if without PD.
5. According to postoperative pathological remission, pCR patients in two groups continued to complete adjuvant targeted therapy based on original treatment. For non-pCR patients in the PTC group, PTC drug sensitivity test will be done again to guide adjuvant therapy, for non-pCR patients in the routine treatment group, Capecitabine for HER2 negative breast cancer, and T-DM1 or H(P) will be selected.
6. All patients will be received radiotherapy or endocrine therapy if necessary.

Inclusion Criteria:

1. Female between 18 to 70 years old.
2. Patients diagnosed with invasive breast cancer by pathology.
3. Clinical stage considered as T2-4N0-2M0 .
4. HER2 overexpression by IHC or FISH positive.
5. Patients plan to accept neoadjuvant therapy or plan to accept adjuvant therapy after neoadjuvant therapy and surgery.

Exclusion Criteria:

1. Patients have already accepted any other anti-tumor treatment not included in our project.
2. Patients with metastasis are not considered surgery therapy.
3. Patients cannot accept chemotherapy or anti-HER2 targeted therapy, because of severe cardiovascular diseases or other reasons