Synthetic peptides that can re-educate the immune to break tolerance to cancer associated antigens has tremendous clinical utility.Over expressed proteins such as Her-2.neu in a subset of human breast cancer is associated with poor prognosis, relapse and metastasis.Using this protein as an experimental model, we identified synthetic peptide mimotopes from two synthetic phage display peptide libraries, LX-8 and X-15 by panning the libraries against different antibodies that recognize the extra-cellular domain of the protein.