SSTR5 (somatostatin receptor 5) is a G-protein coupled receptor that binds somatostatin 28 and, to a lesser extent, somatostatin-14, mediating signaling through inhibition of adenylyl cyclase 1. The receptor is expressed in various tissues including the pituitary, where SSTR2 and SSTR5 predominate and regulate hormone secretion and cell growth 1. SSTR5 is also present in peripheral tissues such as thoracic duct smooth muscle cells 2 and cardiac tissue, where expression is significantly decreased in ischemic cardiomyopathy 3. In neuroendocrine tumors, SSTR5 expression serves as both a diagnostic marker and therapeutic target. Elevated SSTR5 mRNA levels in peripheral blood show high sensitivity (86%) for detecting neuroendocrine lung cancers 4. In pancreatic insulinomas, SSTR5 expression occurs in only 6% of cases but is associated with impaired overall survival 5. Functionally, SSTR5 can enhance the growth inhibitory effects of SSTR2 through heterodimerization and plays a role in mediating responses to glucocorticoid receptor modulators in pituitary tumors 6. The receptor's expression is linked to epithelial-mesenchymal transition and neuroendocrine differentiation in pancreatic cancer cells 7.