Somatostatin receptors expressed on tumor cells form the rationale for somatostatin analog treatment of patients with somatostatin receptor-positive neuroendocrine tumors. Nevertheless, although somatostatin analogs effectively control hormonal hypersecretion by GH-secreting pituitary adenomas, islet cell tumors, and carcinoid tumors, significant differences are observed among patients with respect to the efficacy of treatment. This may be related to a differential expression of somatostatin receptor subtypes among tumors. In addition, the property of somatostatin receptor subtypes to undergo agonist-induced internalization has important consequences for visualizing, as well as for therapy, of receptor-positive tumors using radioisotope- or chemotherapeutic-compound-coupled somatostatin analogs. This review covers the pathophysiological role of somatostatin receptor subtypes in determining the efficacy of treatment of patients with somatostatin receptor-positive tumors using somatostatin analogs, as well as the preclinical and clinical consequences of agonist-induced receptor internalization for somatostatin receptor-targeted radio- and chemotherapy. Herein, the development and potential role of novel somatostatin analogs is discussed.

Animals, Drug Resistance, Gene Expression, Humans, Neoplasms/drug therapy/metabolism/radiotherapy, Radiopharmaceuticals/therapeutic use, Receptors, Somatostatin/analysis/genetics/*metabolism, Somatostatin/pharmacology, Tachyphylaxis
hdl.handle.net/1765/10105
Endocrine Reviews
Erasmus MC: University Medical Center Rotterdam

Hofland, L.J, & Lamberts, S.W.J. (2003). The pathophysiological consequences of somatostatin receptor internalization and resistance. Endocrine Reviews. Retrieved from http://hdl.handle.net/1765/10105