Outcome measures Primary 1. Evaluation of whether the HER2 peptide -based boosters enhance HER2 -specific immunity through IFN -g ELISPOT will be determined 6 months after first and second booster vaccines. Increased HER2 -specific immunity will be defined by generating a HER2 protein specific IFN -g precursor augmented over 2 times baseline. 2. Evaluation of whether there is increased memory T -cell populations in the peripheral blood by flow cytometry will be evaluated 48 hours after each of the two HER2 peptide -based booster vaccinations. The peripheral memory T -cell populations will be evaluated on PBMC using a flow cytometry panel developed in our immune monitoring laboratory. We will be evaluating CD45R0, CD62, CCR7, CD3, CD4, and CD8 antibodies for evaluation of memory T -cells. 3. Evaluation of HER2- specific memory through development of a delayed type hypersensitivity (DTH) response at the vac cination site will be determined 48 hours after each booster vaccine. A positive response will be defined as ≥ 10 mm 2 induration at the vaccination site. 4. Evaluation of immune modulation by FDG -PET will be defined as acute inflammatory response evidenced by acute increase in FDG avidity in the tumor and/or draining lymph nodes 48 hours after the 2nd booster vaccination as compared to baseline FDG -PET prior to the second vaccine. Secondary 1.