title: Somatostatin and dopamine receptor profile of gastroenteropancreatic neuroendocrine tumors: an immunohistochemical study.
abstract: Somatostatin and its synthetic analogs act through five specific somatostatin receptors (sstr1-5), found on the cell membrane of various tumors, including endocrine ones. Dopamine--a known neurotransmitter--acts through five membranous dopamine receptors (D1R-D5R) which have recently been found to be expressed in endocrine tumors. We evaluated the immunohistochemical expression of the sstrs and D2R in a large series of gastroenteropancreatic neuroendocrine tumors (GEP-NETs). A total of 22 (28.94%) well-differentiated NETs (WDNETs), 6 (7.89%) WDNETs of uncertain biology, 26 (34.21%) well-differentiated neuroendocrine carcinomas, and 22 (28.94%) poorly differentiated neuroendocrine carcinomas were studied. Overall, 76.31% of the tumors were positive for different types of sstrs with variable intensity of the membranous staining whereas 36.95% were positive for D2R alone. The sstr2A was the most frequently expressed, followed by sstr2B, sstr1, and sstr5. Co-expression of sstrs and D2R was seen in 88.23% of positive tumors. The high rates of sstr2A and sstr2B and in a lower extent of sstr5 expression are of great importance for more accurate imaging, staging and targeted therapy of the disease. The co-expression of sstrs and D2R in a significant number of the studied cases offers a potential therapeutic alternative for GEP-NETs.
authors.affiliation: Department of Pathology, G. Gennimatas Athens General Hospital, 154 Mesogeion Avenue, 115 27 Athens, Greece. diakva@yahoo.gr
authors.forename: Evanthia
authors.initials: E
authors.lastname: Diakatou
authors.forename: Gregory
authors.initials: G
authors.lastname: Kaltsas
authors.forename: Michail
authors.initials: M
authors.lastname: Tzivras
authors.forename: George
authors.initials: G
authors.lastname: Kanakis
authors.forename: Eugenia
authors.initials: E
authors.lastname: Papaliodi
authors.forename: George
authors.initials: G
authors.lastname: Kontogeorgos
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000378:metabolism; D002648:Child; D004067:Digestive System Neoplasms / Q000378:metabolism* / Q000473:pathology / Q000601:surgery; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D018358:Neuroendocrine Tumors / Q000378:metabolism* / Q000473:pathology / Q000601:surgery; D011954:Receptors, Dopamine / Q000378:metabolism*; D017481:Receptors, Somatostatin / Q000378:metabolism*; D055815:Young Adult
chemical_list: D014408:Biomarkers, Tumor; D011954:Receptors, Dopamine; D017481:Receptors, Somatostatin