Clinical Research Directory

Inclusion Criteria: * Age \>= 18 years * Histological confirmed adenocarcinoma of the breast stage I-IV from the American Joint Committee on Cancer staging 8th edition * Any estrogen receptor (ER) or progesterone receptor (PR) but HER2 positive defined as per the most current American Society of Clinical Oncology (ASCO)/College of American Pathologists (CAP) guideline * Provide written informed consent * Willingness to provide blood samples for correlative research purposes * BLOOD AND TISSUE COHORT: Scheduled to start new anti-HER2 therapy/therapies * TISSUE-ONLY COHORT: Received or previously completed anti-HER2 therapy/therapies Exclusion Criteria: * Immunocompromised patients including patients known to be human immunodeficiency virus (HIV) positive * Receiving systemic steroid therapy or any other immunosuppressive therapy =\< 30 days prior to registration. NOTE: Inhaled steroids, low-dose corticosteroids (e.g. equivalent to or less than oral prednisone 10 mg daily), and steroid use for primary prevention of nausea per institutional guidelines are allowed.