title: Somatostatin receptor 2 and 5 expressions in gastroenteropancreatic neuroendocrine tumors in Turkey.
abstract: BACKGROUND
  Gastroenteropancreatic neuroendocrine tumors (GNs) are slow growing and although their incidence has increased in recent years, they are relatively rarely seen. Somatostatin analogues are used in the treatment of GNs that express somatostatin receptor (SR). We aimed to investigate the expression of SR2 and SR5 in GNs.
  
  
  METHODS
  In this study the expression of SR2 and SR5 was investigated immunohistochemically in 49 cases (26 males, 23 females) diagnosed and graded with GN according to the World Health Organization classification 2010.
  
  
  RESULTS
  The percentage of SR2 staining was 91.0% in grade 1, 82.8% in grade 2 and 100% in grade 3. On the other hand, the percentage of SR5 staining was 81.8% % in grade 1, 60.0% in grade 2 and 0% in grade 3. According to the tumor localization, the percentages of SR2 expression were as follows: pancreas 85.7%, stomach 100%, small bowel 70%, appendix 85.7% and rectum 100%. The percentages of SR5 expression were: pancreas 61,9%, stomach 37.5%, small bowel 70%, appendix 71.5% and rectum 66.6%. There was a significant negative correlation between ki67 percentage and SR5 expression (r=-0.341, p=0.016).
  
  
  CONCLUSIONS
  In this study, GNs were found to highly express SR2 and SR5. Although the expression of SR2 and SR5 changed according to tumor localization, the expression of SR2 was higher than the expression of SR5 in GN. There was a significant negative correlation between ki67 and SR5. Accordingly, SR5 may be a prognostic indicator of GN.
authors.affiliation: Department of Pathology, Faculty of Medicine, Uludag University, Bursa, Turkey E-mail : sehitogluibrahim@gmail.com.
authors.forename: Omer
authors.initials: O
authors.lastname: Yerci
authors.forename: Ibrahim
authors.initials: I
authors.lastname: Sehitoglu
authors.forename: Nesrin
authors.initials: N
authors.lastname: Ugras
authors.forename: Erdem
authors.initials: E
authors.lastname: Cubukcu
authors.forename: Suleyman
authors.initials: S
authors.lastname: Yuce
authors.forename: Recep
authors.initials: R
authors.lastname: Bedir
authors.forename: Erkan
authors.initials: E
authors.lastname: Cure
mesh_terms: D000328:Adult; D000368:Aged; D001063:Appendiceal Neoplasms / Q000737:chemistry / Q000473:pathology; D005260:Female; D005770:Gastrointestinal Neoplasms / Q000737:chemistry* / Q000473:pathology; D006801:Humans; D019394:Ki-67 Antigen / Q000032:analysis; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D018358:Neuroendocrine Tumors / Q000737:chemistry* / Q000473:pathology; D010190:Pancreatic Neoplasms / Q000737:chemistry* / Q000473:pathology; D017481:Receptors, Somatostatin / Q000032:analysis*; D012004:Rectal Neoplasms / Q000737:chemistry / Q000473:pathology; D013274:Stomach Neoplasms / Q000737:chemistry / Q000473:pathology; D014421:Turkey
chemical_list: D019394:Ki-67 Antigen; D017481:Receptors, Somatostatin; C094573:somatostatin receptor 5; C093733:somatostatin receptor 2