title: Somatostatin receptor profiling in hepatic metastases from small intestinal and pancreatic neuroendocrine neoplasms: immunohistochemical approach with potential clinical utility.
abstract: BACKGROUND
  The expression of somatostatin receptors (SSTRs) on endocrine tumor (ET) cells forms the basis for somatostatin analog treatment of patients with SSTR-positive, hormonally active ETs. In patients with SSTR-negative ETs, the clinical response is generally absent or suboptimal, while nonfunctioning ETs with SSTR positivity show a variable response to such therapy.
  
  
  METHODS
  We retrospectively studied SSTR subtype expression in hepatic metastases from 14 adult patients with primary endocrine carcinomas (ECAs) of the small intestine and pancreas and compared SSTR subtype expression among the primary and metastatic ECAs. Polyclonal antibodies against the 5 SSTR subtypes were used on formalin-fixed, paraffin sections from each primary and metastatic ECA. Both qualitative and semiquantitative evaluation of the stained ECA sections was carried out.
  
  
  RESULTS
  Eleven (61%) of 18 hepatic metastases from small intestinal and pancreatic ECAs were positive for SSTR-1, 15 (83%) for SSTR-2, 13 (72%) for SSTR-3, 10 (56%) for SSTR-4, and 15 (83%) for SSTR-5. Among 11 hepatic ECA metastases from small intestinal ECAs (carcinoids), 7 (63%) expressed SSTR-1, 9 (81%) expressed SSTR-2, 8 (72%) expressed SSTR-3, 6 (54%) expressed SSTR-4, and 10 (91%) expressed SSTR-5. Of 7 hepatic ECA metastases from pancreatic ECAs, 4 expressed SSTR-1, 6 expressed SSTR-2, and 5 expressed SSTR-3 and SSTR-5 each. We also observed the immunohistochemical evidence of heterogeneity of expression of various SSTR subtypes in the primary enteropancreatic ECAs and their hepatic metastases.
  
  
  CONCLUSIONS
  SSTR subtype expression needs to be correlated to somatostatin analog therapy. Immunohistochemical profiling of various SSTR subtypes as a part of routine surgical pathologic analysis of enteropancreatic ETs may become a useful predictor of responsiveness of ETs to various SSTR analogs.
authors.affiliation: Gastrointestinal Tumor Program, Neuroendocrine Cancer Research, H. Lee Moffitt Cancer Center & Research Institute, Tampa, FL 33612-9497, USA. anassmir@nc.rr.com
authors.forename: Aejaz
authors.initials: A
authors.lastname: Nasir
authors.forename: Mats
authors.initials: M
authors.lastname: Stridsberg
authors.forename: Jonathan
authors.initials: J
authors.lastname: Strosberg
authors.forename: Phi-Huynh
authors.initials: PH
authors.lastname: Su
authors.forename: Sandra
authors.initials: S
authors.lastname: Livingston
authors.forename: Humaira A
authors.initials: HA
authors.lastname: Malik
authors.forename: Scott T
authors.initials: ST
authors.lastname: Kelley
authors.forename: Barbara A
authors.initials: BA
authors.lastname: Centeno
authors.forename: Domenico
authors.initials: D
authors.lastname: Coppola
authors.forename: Mokenge E
authors.initials: ME
authors.lastname: Malafa
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Yeatman
authors.forename: Larry K
authors.initials: LK
authors.lastname: Kvols
mesh_terms: D000328:Adult; D000368:Aged; D018278:Carcinoma, Neuroendocrine / Q000378:metabolism / Q000556:secondary*; D005260:Female; D006801:Humans; D007414:Intestinal Neoplasms / Q000378:metabolism* / Q000473:pathology; D008113:Liver Neoplasms / Q000378:metabolism / Q000556:secondary*; D008297:Male; D008875:Middle Aged; D010190:Pancreatic Neoplasms / Q000378:metabolism* / Q000473:pathology; D017481:Receptors, Somatostatin / Q000145:classification / Q000378:metabolism*; D012189:Retrospective Studies; D013004:Somatostatin / Q000031:analogs & derivatives*
chemical_list: D017481:Receptors, Somatostatin; D013004:Somatostatin