Neuroendocrine neoplasms and somatostatin receptor subtypes expression

Abstract

Neuroendocrine neoplasms (NENs) show wide spectrum of clinical course — from benign biological potential to recurrences and rapidly progressive disease. Somatostatin analogs that bind to somatostatin receptor are part of the therapy; detection and evaluation of activation of somatostatin receptor subtypes are part of the process of new therapy induction. When using RT-PCR method and immunohistochemistry, it is possible to detect more than two SSTR subtypes in majority or all neuroendo­crine neoplasms regardless tumor origin. Generally with some exceptions, from the viewpoint of tumor grade — apart the site of origin, there is a tendency to decrease the percentage of SSTRs expression; 100% (G1, 2)–85.7% (G3) for SSTR 1; 81.8% (G1, 2)–61.9% (G3) for SSTR 2; 54.5% (G1, 2)–52.4% (G3) for SSTR 3; 9% (G1, 2)–4.8% (G3) for SSTR 5. Different studies indi­cate significant differences in the expression of SSTR 1 and 2A and 2B between NEC G3 small cell type and non-small cell type. Further research on SSTRs expression in NEN could serve as base to development and improvement of somatostatin analogs’ pharmacotherapy in patients with unsatisfactory course.