Safety and Immune Response to a Mammaglobin-A DNA Vaccine In Breast Cancer Patients Undergoing Neoadjuvant Endocrine Therapy

Inclusion Criteria: A patient will be eligible for inclusion in this study only if ALL of the following criteria apply: * Newly diagnosed histologically confirmed invasive breast cancer. * Clinical T2-T4c, any N, M0 invasive ER+ (Allred Score of 6-8) and HER2- (0 or 1+ by IHC or FISH negative for amplification) breast cancer by AJCC 7th edition clinical staging, with the goal being surgery to completely excise the tumor in the breast and the lymph node. Patients with T1c tumors are eligible if they are considered candidates for neoadjuvant endocrine therapy or chemotherapy * At least 1 measurable lesion. * Candidate for neoadjuvant endocrine therapy or chemotherapy. * At least 18 years of age. * Eastern Cooperative Oncology Group (ECOG) performance status ≤2. * Adequate organ and marrow function no more than 28 days prior to the start of neoadjuvant endocrine therapy or chemotherapy as defined below: * WBC ≥3,000/μL * absolute neutrophil count ≥1,500/μL * platelets ≥100,000/μL * total bilirubin ≤institutional upper limit of normal * AST/ALT ≤2.5 X institutional upper limit of normal * creatinine ≤ institutional upper limit of normal OR creatinine clearance ≥ 60 mL/min/1.73 m2 for patients with creatinine above IULN * Postmenopausal or premenopausal. NOTE: Postmenopausal women, verified by: (1) bilateral surgical oophorectomy, or (2) no spontaneous menses ≥ 1 year or (3) no menses for \<1 year with FSH and estradiol levels in postmenopausal range, according to institutional standards. Premenopausal women, verified by: (1) regular menses, or (2) FSH and estradiol levels in premenopausal range, according to institutional standards. * Able to understand, and willing to sign a written informed consent document. * Confirmation that primary tumor expresses mammaglobin-A by IHC. * Clinical assessment by treating physician that the patient is responding to neoadjuvant therapy or umor Ki67 value is ≤ 10% after 14 days Exclusion Criteria: A patient will be ineligible for inclusion in this study if ANY of the following criteria apply: * Received any of the following for treatment of this cancer (except for the neoadjuvant endocrine therapy or chemotherapy specified within this protocol): * Surgery * Radiation therapy * Chemotherapy * Biotherapy * Hormonal therapy * Investigational agent Note that subjects who do not respond initially to endocrine therapy may receive chemotherapy and remain on study. * Receiving any other investigational agent(s) or has received an investigational agent within the last 30 days. * Known metastatic disease. * Known allergy, or history of serious adverse reaction to vaccines such as anaphylaxis, hives, or respiratory difficulty. * Prior axillary lymph node sampling (sentinel lymph node biopsy or axillary lymph node dissection). FNA or core needle biopsy of axillary lymph node is acceptable. * 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 situation that would limit compliance with study requirements. * Prior or currently active autoimmune disease requiring management with immunosuppression. This includes inflammatory bowel disease, ulcerative colitis, Crohn's disease, systemic vasculitis, scleroderma, psoriasis, multiple sclerosis, hemolytic anemia, immune-mediated thrombocytopenia, rheumatoid arthritis, systemic lupus erythematosus, Sjogren's syndrome, sarcoidosis, or other rheumatologic disease or any other medical condition or use of medication (e.g., corticosteroids) which might make it difficult for the patient to complete the full course of treatments or to generate an immune response to vaccines. Asthma or chronic obstructive pulmonary disease that does not require daily systemic corticosteroids is acceptable. Any patients receiving steroids should be discussed with the PI to determine if eligible. * Pregnant or breastfeeding. A negative serum or pregnancy test is required no more than 7 days before study entry, and patients must be willing to employ adequate contraception. Women of childbearing potential must use two forms of contraception (hormonal or barrier method of birth control; abstinence) prior to study entry and for the duration of study participation. * Known HIV-positive status. These patients are ineligible because of the potential inability to generate an immune response to vaccines. * Subjects with a strong likelihood of non-adherence such as difficulties in adhering to follow-up schedule due to geographic distance from the Siteman Cancer Center should not knowingly be registered. * Individuals in whom a skinfold measurement of the cutaneous and subcutaneous tissue for the eligible injection sites (left and right medial deltoid region) exceeds 40 mm * Individuals in whom the ability to observe possible local reactions at the eligible injection sites (deltoid region) is, in the opinion of the investigator, unacceptably obscured due to a physical condition or permanent body art * Therapeutic or traumatic metal implant in the skin or muscle of either deltoid region. * Acute or chronic, clinically significant hematologic, pulmonary, cardiovascular, or hepatic or renal functional abnormality as determined by the investigator based on medical history, physical examination, EKG, and/or laboratory screening test * Any chronic or active neurologic disorder, including seizures and epilepsy, excluding a single febrile seizure as a child * Syncopal episode within 12 months of screening * Current use of any electronic stimulation device, such as cardiac demand pacemakers, automatic implantable cardiac defibrillator, nerve stimulators, or deep brain stimulators.