Expression Of Somatostatin Receptor Subtypes In Pituitary Tumors In

Background:The role of somatostatin receptors as molecular targets for the treatment of patients with pituitary adenomas is well established. Indeed, somatostatin receptor agonists are considered milestones for the medical therapy of these tumours. However, in recent years, the knowledge of the highly variable expression of subtypes of somatostatin receptors in pituitary adenomas has increased considerably. We aimed for detecting the expression of SSTR subtypes in pituitary adenomas and the relationships between SSTR subtypes expression pattern and the therapeutic action of somatostatin analogues.Material and methods:We studied48pituitary adenoma patients, and summarized the data on expression of all somatostatin receptor subtypes (SSTR1-5), revealed by means of immunohistochemistry.Results:The pattern of SSTR subtypes expression result (estimated according to the percentage frequency of appearance) was in acromegaly:SSTR4> SSTR1> SSTR5> SSTR2> SSTR3, in prolactinomas:SSTR1=SSTR4> SSTR5> SSTR2> SSTR3, in corticotropinomas:SSTR4> SSTR3> SSTR1=SSTR5> SSTR2, in TSH-secreting adenoma:SSTR4> SSTR1=SSTR5> SSTR3> SSTR2; in NFPA:SSTR1> SSTR4> SSTR3> SSTR5> SSTR2.Conclusions:Human pituitary adenoma represents a group of tumors with a different appearance of somatostatin receptor subtypes. In hormone-secreting pituitary adenomas, SSTR4is predominant, while in non-function pituitary adenomas, SSTR1is predominant. It is very important to determine the SSTR profile individually for each tumour to make an appropriate decision as to therapeutic strategychoice.