Somatostatin receptor expression in thyroid disease

Abstract

Somatostatin analogues are commercially available and used for the management of acromegaly and neuroendocrine tumours, but the expression of the receptors as a target in thyroid disease has not been explored. To assess somatostatin (SST) and somatostatin receptor (SSTR1-5) expression in both normal and thyroid disorders, as a potential target for somatostatin analogue therapy, 67 thyroid tissue specimens were reviewed: 12 differentiated thyroid carcinomas, 14 follicular adenomas, 17 multinodular goitres, 14 Graves disease, 10 Hashimotos thyroiditis specimens and five normal thyroids. Tissue was immunostained for SST and SSTR1-5. Positivity and the degree of positivity were recorded by double-blinded observers. Somatostatin receptor expression was highly expressed in normal tissue for SSTR1, 3, 4 and 5 (5 of 5, 4 of 5, 4 of 5 and 5 of 5 respectively) whilst SST and SSTR 2a and b were not expressed at all. The commonest receptor expressed for all pathological subtypes grouped together was SSTR2b (63 specimens). The commonest receptors expressed in differentiated thyroid cancer were SSTR5 (11 of 12 specimens) and SSTR2b (10 of 12 specimens). The commonest receptor expressed in benign disease was SSTR2b (53 of 55 specimens). SSTR5 was significantly under-expressed in Graves disease (P < 0.05). This study illustrates that SSTR 1, 3, 4 and 5 are highly expressed in normal, benign and malignant thyroid tissue. SSTR 2a and 2b appear absent in normal tissue and present in benign and malignant thyroid tissue (P < 0.02). This suggests that focussed SSTR2 treatment may be a potential therapeutic target.

The Truncated Isoform of Somatostatin Receptor5 (sst5TMD4) Is Associated with Poorly Differentiated Thyroid Cancer

“…Quantitative evaluation of ssts expression in thyroid cancer has shown some discrepancies, with some authors reporting the expression of sst1, 3 and 5 and others exclusively sst5 by using immunocytochemical techniques [8], [10]. Even with these discrepancies, expression of ssts in both follicular and parafollicular origin thyroid cancer tissue has been recently confirmed by other laboratories [9], [11], [12], [29]–[31].…”

Jak często wykrywamy przypadkowe zmiany w tarczycy w badaniu PET/CT z 68Ga-DOTATATE u pacjentów diagnozowanych z powodu nowotworu neuroendokrynnego?

“…Significant correlation was found between SSTR2 expression and the maximum Standardised Uptake Value (SUVmax) as a semiquantitative parameter on the PET/CT [7]. The visualisation of SSTR2 status in vivo with radiolabelled SST analogues help to define the role of SSTR2 in thyroid diseases.…”

An Immunohistochemical Investigation of the Expression of Somatostatin Receptor Subtypes – Should Therapeutic Trials be Performed to Determine the Efficacy of Somatostatin Analogs in Treating Advanced Thyroid Malignances?

“…for the management of acromegaly [19,20], Cushing disease [21] and neuroendocrine tumors of the gastrointestinal tract (NETs) [22]. Parafollicular C cell-derived medullary thyroid carcinomas (MTC) [23,24], benign thyroid pathologies and WDTC [25][26][27][28] are the most commonly used model for evaluating the SSTR-1-5 in thyroid gland. However, the presence of SSTR-1-5 has not been sufficiently explored in poorly differentiated and undifferentiated thyroid tumors.…”