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

Inclusion 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 Subjects in the cardiotoxicity group (TOX) must meet the following criteria: * 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). Subjects in the no cardiotoxicity group (NO-TOX) must meet the following criteria: * 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 trastu…