title: Glucagon-like peptide-1 versus somatostatin receptor targeting reveals 2 distinct forms of malignant insulinomas.
abstract: Glucagon-like peptide-1 (GLP-1) receptor imaging is superior to somatostatin receptor subtype 2 (sst(2)) imaging in localizing benign insulinomas. Here, the role of GLP-1 and sst(2) receptor imaging in the management of malignant insulinoma patients was investigated.
  
  
  METHODS
  Eleven patients with malignant insulinoma were prospectively included. (111)In-[Lys(40)(Ahx-diethylenetriaminepentaacetic acid [DTPA])NH(2)]-exendin-4 SPECT/CT, (68)Ga- DOTATATE PET/CT, and in vitro receptor autoradiography were performed to assess the receptor status and to evaluate the detection rate.
  
  
  RESULTS
  GLP-1 receptor targeting was positive in 4 of 11 patients, and sst(2) receptor expression was positive in 8 of 11. In only 1 patient were both receptors expressed. In 1 patient, GLP-1 receptor imaging was the only method that successfully localized the primary tumor in the pancreas. In 3 patients with sst(2)-expressing tumors, DOTATATE radiotherapy was effectively applied.
  
  
  CONCLUSIONS
  As opposed to benign insulinomas, malignant insulinomas often lack GLP-1 receptors. Conversely, malignant insulinomas often express sst(2), which can be targeted therapeutically.
authors.affiliation: Institute of Nuclear Medicine, University College Hospital, London, United Kingdom.
authors.forename: Damian
authors.initials: D
authors.lastname: Wild
authors.forename: Emanuel
authors.initials: E
authors.lastname: Christ
authors.forename: Martyn E
authors.initials: ME
authors.lastname: Caplin
authors.forename: Tom R
authors.initials: TR
authors.lastname: Kurzawinski
authors.forename: Flavio
authors.initials: F
authors.lastname: Forrer
authors.forename: Michael
authors.initials: M
authors.lastname: Brändle
authors.forename: Jochen
authors.initials: J
authors.lastname: Seufert
authors.forename: Wolfgang A
authors.initials: WA
authors.lastname: Weber
authors.forename: Jamshed
authors.initials: J
authors.lastname: Bomanji
authors.forename: Aurel
authors.initials: A
authors.lastname: Perren
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Ell
authors.forename: Jean Claude
authors.initials: JC
authors.lastname: Reubi
mesh_terms: D000368:Aged; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D000067757:Glucagon-Like Peptide-1 Receptor; D006801:Humans; D006946:Hyperinsulinism / Q000150:complications; D007003:Hypoglycemia / Q000150:complications; D007340:Insulinoma / Q000150:complications / Q000175:diagnosis* / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D018027:Receptors, Glucagon / Q000378:metabolism*; D017481:Receptors, Somatostatin / Q000378:metabolism*; D015899:Tomography, Emission-Computed, Single-Photon; D014057:Tomography, X-Ray Computed
chemical_list: C000593833:GLP1R protein, human; D000067757:Glucagon-Like Peptide-1 Receptor; D018027:Receptors, Glucagon; D017481:Receptors, Somatostatin