The present invention relates to peptide-based compounds comprising (i) at least one peptide comprising the amino acid sequence of TKDNNLLGRFELXG wherein X is S or T and (ii) at least one label and/or drug. The present invention further relates to the use of said peptide-based compounds for tumor imaging and/or tumor targeting. The present invention further relates to the use of said peptide-based compounds as carrier of tumor therapeutic(s). The present invention further relates to methods for the in vitro and/or in vivo visualization, identification and/or detection of tumor cells and/or metastases as well as to methods for the treatment of cancer. The present invention further relates to a screening method for anti-tumor compounds.
