Studies have shown that dose-dense chemotherapy reduces the risk of recurrence and death of breast cancer patients comparing with standard-schedule chemotherapy. But some research data indicate that HR+/HER2- breast cancer patients benefit from dose-dense chemotherapy while some have negative results. How to identify HR+/HER2 breast cancer patients who are more likely to benefit from dose-dense chemotherapy is strongly necessary. Ki67 is a marker reflecting the proliferation of tumor cells. Breast cancer patients with high Ki67 are more likely to benefit from dose-dense chemotherapy. The purpose of this project is to investigate the efficacy and safety of neoadjuvant dose-dense chemotherapy for HR+/HER2- breast cancer patients with high proliferation index. At the same time, we will explore biomarkers, such as MammaPrint and BluePrint, to further identify patients who benefit more from neoadjuvant dose-dense chemotherapy.

Inclusion Criteria:

• Females with age of 18 to 70 years old.
• Newly diagnosed breast cancer patients.
• Planned neoadjuvant chemotherapy.
• Hormone receptor status: Estrogen receptor (ER)-positive or Progesterone Receptor (PR)- positive.
• HER2/neu-negative.
• Ki67≥30%.
• Clinical stage IIB-IIIC.
• Informed consent form understood and signed.
• Patient agrees to all follow-up visits.
• Eastern Cooperative Oncology Group (ECOG) performance status 0 to 1.
• Women of childbearing potential must have a negative serum pregnancy test.

Exclusion Criteria:

• Metastatic disease
• Pregnancy.
• Nursing mothers.
• Active or uncontrolled infection.
• Presence of another malignancies.
• Granulocyte count < 1.5*10^9/L.
• Platelet count < 100*10^9/L.
• Hemoglobin < 90g/L.
• Serum Creatinine more than 1.5 upper limit.
• AST and ALT more than 2.5 upper limit.
• LVEF< 50%.