Cholecystokinin-2 receptor (CCK2R), a member of the G-protein coupled receptor (GPCR) family, is a membrane-bound transmembrane protein that is highly expressed in various neuroendocrine tumors (NETs), including those of small cell lung cancer (SCLC), and medullary thyroid carcinoma (MTC), while exhibiting low expression in most normal tissues 1-4. Here, CCKBR is linked to small cell lung carcinoma.