A vaccine composed of a phosphorylated peptide from the tumor associated antigen insulin receptor substrate-2 (IRS2) and a tetanus-derived peptide, with potential immunomodulating and antineoplastic activities. Upon administration of pIRS2 phosphopeptide-tetanus peptide vaccine, the pIRS2 phosphopeptide may stimulate the immune system to mount a cytotoxic T-lymphocyte (CTL) response against phosphopeptide-containing tumor cells. The tetanus peptide serves as an immunoadjuvant and induces a helper T-cell response which may help stimulate an immune response against the pIRS2-expressing melanoma tumor cells. IRS2 is upregulated in a variety of cancer cells.