title: Expression of somatostatin receptor subtypes in primary and recurrent gonadotropinomas: are somatostatin receptors involved in pituitary adenoma recurrence?
abstract: OBJECTIVE
  Surgical treatment of pituitary macroadenomas often fails because of tumor recurrence after the operation. The causes of tumor recurrence are complex, but one of them may be the high growth potential of the adenoma. As somatostatin receptors mediate antiproliferative, anti-angiogenic and pro-apoptotic actions, it seemed reasonable to investigate their expression in dependence on the adenoma recurrence.
  
  
  METHODS
  Samples of primary and recurrent gonadotropinomas excised surgically from patients were examined. This type of pituitary adenomas was chosen because of its relatively high recurrence rate. The adenoma phenotype and expression of somatostatin receptor subtypes 1-5 (SSTR 1-5) were investigated by immunohistochemistry, and the level of SSTR expression was semiquantitatively scored.
  
  
  RESULTS
  It was found that the adenomas undergoing the early recurrence have lower expression of SSTR 2A and 3 in comparison to those which did not recur during 5 years lasting observation. On the other hand, the recurrent tumors show higher expression of SSTR 1, 2A, 3 and 5 subtypes than their primary counterparts.
  
  
  CONCLUSIONS
  It is hypothesized that SSTR may, at least in part, counteract adenoma recurrence. On the other hand, it can be also presumed that the recurrent gonadotropinomas may be more sensitive to somatostatin analog treatment than primary ones. These hypotheses need to be confirmed in further studies.
authors.affiliation: Department of Neuroendocrinology, Medical University of Łódź, Poland.
authors.forename: Hanna
authors.initials: H
authors.lastname: Pisarek
authors.forename: Jolanta
authors.initials: J
authors.lastname: Kunert-Radek
authors.forename: Maciej
authors.initials: M
authors.lastname: Radek
authors.forename: Jacek
authors.initials: J
authors.lastname: Swietoslawski
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Winczyk
authors.forename: Marek
authors.initials: M
authors.lastname: Pawlikowski
mesh_terms: D000236:Adenoma / Q000378:metabolism* / Q000473:pathology; D000328:Adult; D000368:Aged; D001706:Biopsy; D005260:Female; D006065:Gonadotropins, Pituitary / Q000378:metabolism*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000378:metabolism* / Q000473:pathology; D010911:Pituitary Neoplasms / Q000378:metabolism* / Q000473:pathology; D017481:Receptors, Somatostatin / Q000378:metabolism*
chemical_list: D006065:Gonadotropins, Pituitary; D017481:Receptors, Somatostatin; C103631:somatostatin receptor 3; C098681:somatostatin receptor subtype-4; C101130:somatostatin receptor type 1; C094573:somatostatin receptor 5; C093733:somatostatin receptor 2