DIG-HIF-1 Pharmacodynamic Trial in Newly Diagnosed Operable Breast Cancer

Inclusion Criteria:

* Female sex
* 18-70 years of age at time of consent.
* Histologically confirmed infiltrating carcinoma of the breast (Stage I-III)
* Unresected disease that meets scheduled to undergo definitive surgery; tumor size ≥ 1cm; grade 2 or 3 tumor or Ki-67 proliferation index of ≥ 10%; and, any estrogen receptor (ER), progesterone receptor (PR) or human epidermal growth factor receptor 2 (HER2) status
* Patients must not have received any prior treatment of any kind to treat the current breast cancer.
* Prior use of hormone contraceptives and replacement therapy is allowed, but must have been discontinued at least 30 days prior to the diagnostic biopsy.
* Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1 (Karnofsky 80%-100%)
* Patients must have normal organ and marrow function: absolute neutrophil count (ANC) ≥ 1,500/mm3; platelet count ≥ 100,000/mm3; bilirubin (total) less than or equal to the upper limit of normal; creatinine ≤ 1.5 times the upper limit of normal with creatinine clearance ≥ 50 mL/min using the Modified Cockcroft-Gault method; and, all of the following within normal limits: thyroid stimulating hormone (TSH), magnesium, potassium, sodium, calcium.
* Heart rate \> 60 beats/minute and \< 100 beats/minute (clinical exam).
* Not pregnant or nursing
* Ability to understand and the willingness to sign a written informed consent document

Exclusion Criteria:

* Current use of any investigational agents
* Radiological evidence of metastatic disease
* History of allergic reactions attributed to compounds of similar chemical or biologic composition to digoxin
* Concomitant use of these drugs at baseline and for the duration of digoxin administration (if randomized to receive it): the calcium channel blockers diltiazem or verapamil; cardiac arrhythmic agents (such as quinidine, amiodarone); indomethacin (Indocin); alprazolam (Xanax); diuretics (such as furosemide, spironolactone, itraconazole); beta-blockers (such as atenolol, metoprolol); calcium carbonate antacids (e.g., Maalox, Tums, Rolaids); proton pump inhibitors; antidiarrheal adsorbents (kaolin and pectin); antibiotics; other P450 inducer/inhibitors. Note: Patients already receiving digoxin are also excluded.
* Presence of any of the following on electrocardiogram (ECG): atrial arrhythmias, including atrial fibrillation and flutter; AV block; heart rate \< 60 beats/minute and \> 100 beats/minute; ventricular Fibrillation; ventricular tachycardia; premature ventricular contractions; Wolff-Parkinson-White syndrome. Note: Any questions on cardiac eligibility should be reviewed by the Study Cardiologist for approval in advance of enrollment.
* History of any of the following, unless approval is given by the Protocol Chair: heart disease, including acute myocardial infarction; cardiac arrhythmias, including sick sinus syndrome; pulmonary disease with a known forced expiratory volume (FEV) of \<1.5 or on oxygen; gastrointestinal disease, surgery or malabsorption that could potentially impact the absorption of the study drug; patients requiring the use of a feeding tube; inability to swallow tablets
* Uncontrolled intercurrent illness including, but not limited to, ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, or psychiatric illness/social situations that will limit compliance with study requirements
* Any medical condition which in the opinion of the investigator puts the patient at risk of potentially serious complications while on this therapy