Introduction: Previous studies demonstrated that the lactose-binding protein (hepatocellular carcinoma-intestine-pancreas and pancreatitis-associated proteins (HIP/PAP)) is upregulated >130 times in peritumoral pancreatic tissue as compared to normal pancreatic tissue. Therefore, we developed a new radiolabeled ligand of HIP/PAP, the ethyl-β-D-galactopyranosyl-(1,4')-2'-deoxy-2'-[¹⁸F]fluoro-β-D-glucopyranoside (Et-[¹⁸F]FDL) for noninvasive imaging of pancreatic carcinoma using positron emission tomography and computerized tomography (PET/CT).
Methods: The novel precursor and radiolabeling methods for synthesis of Et-[¹⁸F]FDL produced no isomers; the average decay-corrected radiochemical yield was 68%, radiochemical purity >99%, and specific activity >74 GBq/µmol. The radioligand properties of Et-[¹⁸F]FDL were evaluated using an ex vivo autoradiography and immunohistochemistry in pancreatic tissue sections obtained from mice-bearing orthotopic pancreatic tumor xenografts.
Results and discussion: Et-[¹⁸F]FDL binding to peritumoral pancreatic tissue sections strongly correlated with HIP/PAP expression (r = 0.81) and could be completely blocked by treatment with 1 mM lactose.
Conclusion: These results suggest that Et-[¹⁸F]FDL is a promising agent which should be evaluated for detection of early pancreatic carcinomas by PET/CT imaging.