Endocrine Abstracts

Introduction: The multimodal management of poorly differentiated thyroid carcinomas (PDTC) and anaplastic carcinomas (ATC) include surgical thyroidectomy, radioiodine treatment, and cytotoxic chemotherapy. Patients with distant metastases which do not respond to radiotherapy could be treated with new therapeutic possibilities like tyrosine kinase inhibitors. PPARγ or mutant P53 are also candidates to PDTC and ATC treatment. Somatostatin and its analogs, demonstrate antiproliferative, anti-angiogenic, and pro-apoptotic actions. The expression of the receptors in thyroid cancers was mainly investigated in medullary thyroid carcinomas (MTC), benign thyroid pathologies, and well differentiated thyroid cancers. In PDTC and ATC its presence has not been sufficiently explored. The aim of this study was to investigate the SSTR 1–5 expression in PDTC and ATC using immunohistochemical method and discuss their usefulness as an alternative to conventional forms of therapy.

Materials and method: The investigated group consisted of 18 archived thyroid cancer tissues: 14 PDTC and four ATC. The analysis of SSTR subtypes expression was performed by immunohistochemical method using rabbit polyclonal antisera raised against specific human somatostatin receptor subtypes and the Dako REAL EnVision Detection System.

Results: Analysis performed on 14 samples with PDTC revealed the equal expression of SSTR-1 and SSTR-5 with score ≥2.0 in 10 tumors (71.43%). SSTR-2A positive staining was observed in 5/14 (35.71%), SSTR-2B in 4/14 (28.57%), and SSTR-3 in 3/14 (21.42%) samples. Otherwise, the SSTR 1, 2B and five with score ≥2.0 were expressed in all ATC. SSTR 2A and 3 were observed in 50% of samples. The SSTR subtypes were localized in membranes and in the cytoplasm of tumoral cells.

Conclusions: The somatostatin multiligand or selective agonists should be considered as an alternative to conventional therapeutic agents in PDTC and ATC.