Neoadjuvant Propanolol in Breast Cancer

* Patients will be recruited from the Garbar Breast Care Center and University Medical Center following diagnosis of invasive breast cancer by breast biopsy. * The sympatholytic nonselective beta blocker propranolol will be administered to all participants in a non-randomized manner at an equal dose of 1.5 mg/kg/day. * Following surgical resection of the tumor , the primary endpoint of this study is quantified by comparing the proliferative index of the tumor before propranolol administration (quantified using the initial tumor biopsy) and after 3 weeks of propranolol (quantified using the surgically resected tumor). * Additional molecular analyses and evaluation of safety and toxicity will also be performed to better understand the effects of this treatment on breast cancers and patient adherence to the drug.