Generation of Heart Muscle Cells From Blood or Skin Cells of Breast Cancer Patients

Eligibility Criteria

• * Female
• * Age greater than 18 years
• * Willing to participate in protocol procedures with signed informed consent
• * Assessment of LVEE via echocardiogram, cardiac MRI, or MUGA
• * History of HER2 positive breast cancer (stage I-IV)
• * Prior/current treatment with anthracycline based chemotherapy followed by anti-HER2 directed therapy or anti-HER2 directed therapy alone
• * Assessment of LVEF at baseline prior to initiation of anthracycline or anti-HER2 therapy and during anti-HER2 therapy via echocardiogram, cardiac MRI, or MUGA
• * Prior confirmed diagnosis of cardiotoxicity associated with anti-HER2 based therapy, defined as a decrease in LVEF \> 10% from baseline to \< 53% with symptoms of heart failure (NYHA class II-IV).
• * History of HER2 positive breast cancer (stage I-IV)
• * Completion of planned anthracycline and anti-HER2 therapy, or anti-HER2 therapy alone
• * No symptoms of heart failure (NYHA class II-IV) during and at the end of anthracycline and anti-HER2 therapy
• * Assessment of LVEF at baseline prior to innitiation of anthracycline or anti-HER2 therapy and during anti-HER2 therapy via echocardiogram, cardiac MRI, or MUGA
• * Normal LVEF \>53% at each assessment during and at the end of trastuzumab therapy.
• * Maximum absolute decrease in LVEF \<5% from baseline during and at the end of trastuzumab therapy.
• * LVEF assessment performed at baseline and at least two time points during trastuzumab therapy.
• * Unwilling or unable to give skin biopsies
• * Contraindications to punch biopsy including but not limited to bleeding diathesis, as determined by the investigator.
• * Known pre-existing CV disease prior to initiation of breast cancer therapy as determined by the investigator, including
• * Obstructive coronary artery disease (stenosis \>70%)
• * Arrhythmia - paroxysmal or persistent atrial arrhythmias, sustained ventricular tachycardia (\>30 seconds), ventricular fibrillation, or cardiac arrest
• * Cardiomyopathy (EF \<53%)
• * Heart failure (NYHA class II-IV)
• * Valvular heart disease with equal to or greater than moderate stenosis or regurgitation