The present invention provides HLA-DR (MHC class II) binding peptides derived from the ovarian/breast cancer associated antigens, Human Epidermal Growth Factor Receptor 2 (HER-2/neu), Carcinoembryonic Antigen (CEA), Insulin Growth Factor Binding Protein 2 (IGFBP-2), and Cyclin D1. The immunogenic peptides can be used in cancer vaccines.