Estrogen for Triple Negative Breast Cancer

Inclusion Criteria:

• histologically or cytologically confirmed breast cancer which is metastatic.
• A formalin-fixed paraffin embedded tumor block (preferred) or unstained slides must be available from either a prior biopsy of the primary tumor or a metastatic site. .
• Primary tumor or metastatic biopsy lacking estrogen and progesterone receptor and Her2 negative
• Patients must have measurable disease.
• Eastern Cooperative Oncology Group performance status 0-1.
• Patients with bone metastasis at baseline must agree to treatment with intravenous bisphosphonates
• Subjects may have had 0-4 lines of prior systemic chemotherapy or targeted therapy regimens administered for treatment of their metastatic breast cancer.
• Age >18 years
• Life expectancy of greater than 3 months.
• Patients must have adequate organ and marrow function as defined below:

Exclusion Criteria:

• systemic chemotherapies, targeted therapies or radiotherapy for their cancer within 2 weeks prior to entering the study
• Patients receiving any other investigational agents for breast cancer treatment.
• Patients with known brain metastases are excluded 3.2.4 History of allergic reactions attributed to compounds of similar chemical or biologic composition to estradiol.
• Patients with any condition of the gastrointestinal tract that is expected to result in an inability to take oral medication
• Dysfunctional or post-menopausal vaginal bleeding.
• Uncontrolled hypercalcemia/hypocalcemia
• Prior history of or active thrombophlebitis, cerebral vascular accident, myocardial infarction, deep venous thrombosis or pulmonary embolism.
• History of or active hepatic adenoma.
• Uncontrolled intercurrent illness
• Pregnant women are excluded from this study
• Patients with bone metastasis are excluded if they are unable to receive intravenous bisphosphonate therapy due to the risk for developing hypercalcemia.