A peptide cancer vaccine comprised of human leukocyte antigen HLA-A2-restricted peptide derived from a metastatic melanoma cell line of patient NA17, with potential immunomodulating and antineoplastic activity. NA17.A2 peptide vaccine may stimulate a cytotoxic T lymphocyte (CTL) response against tumors that express this antigen, which may result in a reduction in tumor size. This NA17 specific antigen, encoded by an intron sequence of N-acetylglucosaminyltransferase V (GnT-V) gene, is expressed in about 50% of melanomas.