Over the last twenty years, CCK2R, expressed at high incidence and density in medullary thyroid carcinoma (MTC) and small-cell lung cancer (SCLC) among other malignancies, emerged as an attractive target for the development of diagnostic and therapeutic targeted radiopharmaceuticals based on gastrin and cholecystokinin analogues [11,12]. The gene discussed is GAST; the disease is medullary thyroid gland carcinoma.