title: Expression of the SST receptor 2 in uveal melanoma is not a prognostic marker.
abstract: BACKGROUND
  Uveal melanoma (UM) cells and neurohormone-producing cells both originate from the neural crest. Somatostatin receptors subtype 2 (SSTR2) are over-expressed in several tumors, often from neuroendocrine origin, and synthetic antagonists like octreotide and octreotate are being used as diagnostic or therapeutic agents. We investigated the SSTR2 expression in UM, and determined whether this expression was related to prognosis of the disease.
  
  
  METHODS
  UM cell lines and fresh primary UM samples were tested for SSTR2 expression by autoradiography (AR) using 125I-Tyr3-octreotate. Furthermore, UM cell lines were analyzed for SSTR2 mRNA expression with quantitative real-time RT-PCR.
  
  
  RESULTS
  Using AR, cell-surface SSTR2 expression was demonstrated in two UM metastatic cell lines, but no expression was detected in three cell lines derived from primary UM. However, all primary and metastatic UM cell lines showed mRNA expression levels for SSTR2 using quantitative real-time RT-PCR. Only three of 14 primary UM demonstrated moderate SSTR2 expression, and this expression was not significantly associated with tumor-free survival or any tested prognostic factor.
  
  
  CONCLUSIONS
  Based on the rare and low expression of SSTR2 found in primary UM specimens and in UM cell lines, we conclude that SSTR2 is not widely expressed in UM. Furthermore, SSTR2 expression was not associated with tumor-free survival and prognostic factors. Therefore SSTR2 is not suited as prognostic marker or therapeutic target in UM.
authors.affiliation: Department of Ophthalmology, Erasmus MC, Rotterdam, The Netherlands. m.el_filali@lumc.nl
authors.forename: Mariam
authors.initials: M
authors.lastname: Kouch-el Filali
authors.forename: Emine
authors.initials: E
authors.lastname: Kilic
authors.forename: Marleen
authors.initials: M
authors.lastname: Melis
authors.forename: Annelies
authors.initials: A
authors.lastname: de Klein
authors.forename: Marion
authors.initials: M
authors.lastname: de Jong
authors.forename: Gregorius P M
authors.initials: GP
authors.lastname: Luyten
mesh_terms: D000368:Aged; D000818:Animals; D001345:Autoradiography; D014408:Biomarkers, Tumor / Q000378:metabolism*; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000378:metabolism; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008545:Melanoma / Q000378:metabolism* / Q000473:pathology / Q000556:secondary; D008875:Middle Aged; D010190:Pancreatic Neoplasms / Q000378:metabolism / Q000473:pathology; D011379:Prognosis; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017481:Receptors, Somatostatin / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014604:Uveal Neoplasms / Q000378:metabolism*
chemical_list: D014408:Biomarkers, Tumor; D012333:RNA, Messenger; D017481:Receptors, Somatostatin; C093733:somatostatin receptor 2