Somatostatin receptors: localization and imagining methods (review)

Abstract

Neuroendocrine tumors (NET) is a rare pathology characterized by dysfunction of the pituitary gland and endocrine glands. The survival prognosis depends on the stage of the disease at which the malignant growth was detected.The study objective was to summarize information on the methods of early diagnosis of NETs and antitumor therapy using peptide hypothalamic hormone somatostatin analogues.The review provides a chronological analysis of studies of the expression of somatostatin receptors (SSTRs) in different tissues and organs, methods of their visualization and quantitative determination over 50 years. The expression of SSTRs was revealed on NET cell membranes. The history of SSTRs study dates back to 1972, when somatostatin was first isolated and its structure established. Later, the peptide therapeutic activity in the treatment of NET, realized through somatostatin receptors, was discovered, and a number of somatostatin analogues were synthesized. Five main types of SSTRs are known, including subtypes which are expressed in characteristic volumes in the corresponding pathologies. Determining the expression of SSTRs provides diagnosis and staging of malignant neoplasms. Now the regulation of tumor growth is carried out by synthetic somatostatin analogues. SSTRs imaging is an important stage in planning NET therapy with drugs of this pharmacological group. Clinical studies of the therapy of tumors of various organs and tissues, in vitro and in vivo imaging are being carried out, methods for detecting SSTRs are being studied and compared.A retrospective analysis of the methods used to visualize SSTRs and diagnose and treat NETs is presented. It has been shown that positron emission tomography combined with computed tomography, using SSTRs-binding radioligands is the safest and most accurate method for visualizing SSTRs and diagnosing NETs.