A cancer vaccine comprised of a synthetic peptide with an amino acid sequence corresponding to positions 154-163 of the amino acid sequence for prostate-specific antigen (PSA) with a leucine substitution at position 155. Upon administration, PSA:154-163(155L) peptide vaccine may elicit a cytotoxic T-cell response against tumor cells that express PSA. Check for active clinical trials using this agent. (NCI Thesaurus)