The study is a prospective multi-center randomized control clinical trial which is sponsored by the researchers. The purpose of this study is to determine the effectiveness of adjuvant endocrine therapy for operable ER-beta positive, ER-alpha/PR negative, Her-2 negative breast cancer(triple negative breast cancer, TNBC) patients. The ER-beta positive TNBC patients who had undergone modified radical mastectomy or breast-conserving surgery were randomly (1:1) enrolled to receive toremifene (60 mg per day for premenopausal and perimenopausal patients) /anastrozole(1mg per day for postmenopausal patients) or observation within 4 weeks after adjuvant chemotherapy and/or radiation therapy if necessary.The follow-up time will be at least five years. The disease free survival(DFS) and overall survival(OS) between endocrine group and observation group will be compared to evaluate the effectiveness.

Inclusion Criteria:

• The patients signed the written informed consent.
• The patients present with histologically proven operable invasive breast cancers without distant metastasis.
• The breast tumor's positive ER/PR rate is <1%, and positive ER-beta rate is ≥1% by immuno-histochemistry(IHC).
• The patients have no history of neoadjuvant hormone therapy.
• The patients' Karnofsky performance score ≥70%.
• Female patient who is ≥ 18yrs, and ≤ 80yrs.
• The patients are non-pregnant, and disposed to practice contraception during the whole trial.
• The patients underwent neoadjuvant chemotherapy plus surgery or directly modified radical mastectomy or breast-conserving surgery (plus sentinel lymph node biopsy or axillary lymph node dissection) after diagnosis of breast cancer.
• The patients underwent chemotherapy, radiation therapy after surgery according to the 2013 NCCN guideline.
• The results of patients' blood tests are as follows:

Hb≥90g/L; WBC≥4.0×109/L; Neutrophils≥1.5×109/L; Plt≥100×109/L; alanine aminotransferase(ALT) and aspartate aminotransferase (AST) ≤ 2.5 × upper limit of normal(ULN); total bilirubin(TBIL) ≤ 1.5×ULN; Creatinine ≤ 1.25×ULN.

Exclusion Criteria:

• The patients have a previous history of invasive malignant disease (breast cancer at any time, other malignant disorders within the past 10 years excluding squamous or basal-cell carcinoma of the skin or carcinoma in situ of the cervix, adequately cone biopsied).
• The patients have any severe concomitant disease which will place the patient at unusual risk or confound the results of the trial.
• The patients have history of neoadjuvant hormone therapy.
• The patients are undergoing current administration of anti-cancer therapies, or are attending other clinical trials.
• The patients are pregnant or lactational, or they refuse to practice contraception during the whole trial.
• The patients are unwilling to stop any hormonal drug including hormone replacement therapy(HRT).
• The patients can't understand the written informed consent; such as they have dementia.
• The patients have allergic history or contraindication of toremifene/anastrozole.