After completing standard of care therapy, high-risk, disease-free breast cancer pts with HER2 LE (IHC 1+, 2+) or OE (IHC 3+) tumors are eligible for enrollment in our phase II trial evaluating the HER2-derived peptide vaccines, AE37 (MHC Class II, HLA-nonrestricted epitope) and GP2 (MHC Class I, HLA-A2 + restricted epitope). This evidence concerns the gene GP2 and breast cancer.