The present invention pertains to the field of anti-cancer vaccines. More particularly, the invention concerns an optimized polypeptide, which comprises three cryptic tumor peptides with enhanced immunogenicity and comprises the amino acids sequence YLQVNSLQTVYLEYRQVPVYLEEITGYL, for use in an anti-cancer vaccine. Nucleic acids encoding such a polypeptide, as well as complexes and dendritic cells engineered with this polypeptide or a nucleic acid encoding it, are also part of the invention.