A new TAG-72 cancer marker peptide identified by phage display

UMMS Affiliation

Department of Radiology, Division of Nuclear Medicine



Document Type


Medical Subject Headings

Adenocarcinoma; Amino Acid Sequence; Antigens, Neoplasm; Bacteriophages; Blotting, Western; Cell Line, Tumor; Colonic Neoplasms; Consensus Sequence; DNA Primers; Flow Cytometry; Glycoproteins; HT29 Cells; Humans; Peptide Fragments; *Peptide Library; Tumor Markers, Biological


Neoplasms | Radiology


Radiolabeled peptides as markers of cancer targets have demonstrated their value in diagnostic imaging and radiotherapy. The 16 mer f88-4/Cys6 phage display library was applied to affinity purified TAG-72 and three consensus peptides were identified: VHHSCTKLTHCCQNWH (A2-13), GGVSCMQTSPVCENNL (A2-6) and TKRDCSAQNYGCQKAI (A2-11). The A2-13 and A2-6 phages showed the highest percent binding to LS-174T cells by flow cytometry and were 3-fold higher than a control phage, while fluorescence microscopy showed that both A2-6 and A2-13 phages bound to the LS-174T cell membrane. However, only the A2-6 phage demonstrated specificity by low binding to the TAG-72 negative cell HT-29. Furthermore, the synthesized free A2-6 peptide demonstrated specific binding to LS-174T cells by flow cytometry and by immunohistochemical staining of xenograft tumor compared to normal colon. These data indicate that the A2-6 peptide is specific for the TAG-72 cancer target.

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Citation: Cancer Lett. 2008 Dec 8;272(1):122-32. doi: 10.1016/j.canlet.2008.07.009. Link to article on publisher's site

Related Resources

Link to Article in PubMed


Phage display, TAG-72, Tumor imaging, Peptide biomarker

PubMed ID