Small cell lung cancer in an elderly patient: efficacy of somatostatin analog treatment, a case report.

enolase (NSE), the group of chromogranins, and synaptophysin; when proteins are released into the blood, they can result in a clinically functioning neuroendocrine syndrome [5]. It has been demonstrated by in vitro studies that NETs of the lung can overexpress several peptide receptors: somatostatin receptors (SSTRs) are the most common, although other peptides have been reported less frequently, such as vasoactive intestinal peptide (VIP), cholecystokinin (CCK), neurotensin, bombesin/gastrin-releasing peptide, atrial natriuretic peptide (ANP), calcitonin and calcitonin gene-related peptide (CGRP), oxytocin, and glucagon-like peptide-1 [6]; these findings have been confirmed in vivo by Octreoscan evaluation and immunohistochemistry [7]. In the chest, besides in NETs, SSTR have also been demonstrated in granulomatous diseases, like sarcoidosis and other immune-mediated disorders such as anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis [8]. Their expression was occasionally demonstrated in non-small cell lung cancer (NSCLC) [9]. The activity of somatostatin (SS) is due to its interaction with a family of transmembrane receptors, the SSTR family, including 5 different G-protein-coupled receptors (from SSTR1 to SSTR5). Recently, several peptides like octreotide or lanreotide have been discovered, with similar binding affinity as SS to its receptors and similar activity [10]. Those derivatives of somatostatin are effective in the secretory regulation of NET cells; however, they have been disappointing as antiproliferative agents in vivo for gastrointestinal carcinoids [11]; in contrast, in vitro experiments have shown effective inhibition of cell proliferation in lung NETs by somatostatin analogs [12], although there are only few and non-conclusive clinical reports [13, 14]. Another clinical use of SS analogs is related to the possibility of visualizing SSTRpositive tumors and mapping their localizations by injecting labeled peptides [15].