Patients with HER2+ intraductal carcinoma vaccinated before surgical resection with DCs pulsed with HER-2/neu HLA class I and II peptides and activated in vitro with IFN-gamma and bacterial lipopolysaccharide, showed accumulation of T lymphocytes and B lymphocytes in the breast, and induction of complement-dependent, tumor-lytic antibodies. This evidence concerns the gene ERBB2 and ductal breast carcinoma in situ.