Adjuvant Endocrine Therapy for Estrogen Receptor-beta Positive Triple Negative Breast Cancer

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.