1. pre-menopausal breast cancer patients aged less than 50 years old.

2. Pathology confirmed invasive dutal carcinoma or invasive lobular carcinoma.

3. receiving breast conserving surgery or mastectomy with/without reconstruction; sentinel lymph node biopsy or axillary lymph node dissection.

4. TNM staging: T1b-T2N0-1M0.

5. molecular subtype: ER positive/HER2 negative.

6. MammaPrint testing before initiation of adjuvant therapy.

MammaPrint Value for Pre-menopausal Breast Cancer Patients