Incretin receptor imaging: A new option for NETs

In the first trial of its kind, a new type of peptide receptor is being targeted in neuroendocrine tumor (NET) imaging, which could reveal previously hidden cancer, according to a study published April 17 in the Journal of Nuclear Medicine.

Eleni Gourni, PhD, from the German Cancer Consortium, University Hospital Freiburg and German Cancer Research Center in Heidelberg, Germany, and colleagues evaluated potential compounds for imaging of the glucose-dependent insulinotropic polypeptide (GIP) receptor in this preclinical study.

“A new family of peptide receptors, the incretin receptor family, overexpressed on many neuroendocrine tumors (NETs) is of great importance because it may enable the in vivo peptide-based receptor targeting of a category of NETs that does not express the somatostatin receptor.”

The compounds were conjugated with Indium-111 and Gallium-68 and tested using pancreatic endocrine cell lines in mice. Results showed that GIP compounds were bound to GIP receptors with high affinity. One compound in particular, EG4, showed encouraging uptake and tumors were clearly represented using PET.

“The evaluation of EG4 as a proof-of-principle radioligand indicated the feasibility of imaging GIP receptor–positive tumors,” concluded Gourni et al. “These results prompt us to continue the development of this family of radioligands for imaging of a broad spectrum of NETs.”