We showed in previous studies that HER-2pos DCIS patients vaccinated with IL-12-secreting dendritic cells pulsed with HER-2 peptides not only generated strong Th1 immune responses evident in peripheral blood, but also developed heavy infiltrates of both CD4pos T cells as well as B lymphocytes into the area of disease in the breast [3]. This evidence concerns the gene ERBB2 and ductal breast carcinoma in situ.