Thus, medullary thyroid carcinomas (MTC) represent the most frequently CCK2R-expressing tumors (92%) [130], followed by astrocytomas (65%) [131] and small cell lung cancers (57%) [132], as opposed to non-small cell lung cancers showing no CCK2R expression [129]. The gene discussed is CCKBR; the disease is medullary thyroid gland carcinoma.