PRIMARY OBJECTIVES: I. To determine the safety of intradermal administration of 3 doses of a plasmid-based DNA vaccine encoding the ICD of HER2 administered with a fixed dose of GM-CSF. II. To determine whether a plasmid DNA vaccine encoding the ICD of HER2 can elicit HER2 specific immune responses. SECONDARY OBJECTIVES: I. To determine if the dose of the plasmid-based DNA vaccine effects immunologic responses. II. To determine the persistence of DNA at the site of vaccination. OUTLINE: This is a dose-escalation study of a plasmid-based DNA (pNGVL3-hICD) vaccine. Patients receive pNGVL3-hICD vaccine admixed with GM-CSF intradermally once a month for 3 months in the absence of disease progression or unacceptable toxicity. After completion of study treatment, patients are followed up periodically for up to 15 years with primary physicians.