Table 2: Peptide receptors which have potential in cancer therapy.

Peptide receptorsReceptor subtypesExpressing tumor typeTargeting agents

Somatostatinsst1, sst2, sst3, sst4, and sst5GH-producing pituitary adenoma, paraganglioma, nonfunctioning pituitary adenoma, pheochromocytomasRadioisotopes, AN-201 (a potent cytotoxic radical 2-pyrrolinodoxorubicin), doxorubicin
Pituitary adenylate cyclase activating peptide (PACAP)PAC1Pheochromocytomas
and paragangliomas
Radioisotopes, doxorubicin
Vasoactive intestinal peptide (VIP/PACAP) VPAC1, VPAC2 Cancers of lung
stomach, colon, rectum, breast, prostate, pancreatic ducts,
liver, and urinary bladder
Radioisotopes, camptothecin
Cholecystokinin (CCK) CCK1 (formerly CCK-A) and CCK2Small cell lung cancers, medullary
thyroid carcinomas, astrocytomas, and ovarian cancers
Radioisotopes, cisplatin
Bombesin/gastrin-releasing peptide (GRP)BB1, GRP receptor subtype (BB2), the BB3 and BB4 Renal cell, breast, and
prostate carcinomas
Doxorubicin, 2-pyrrolinodoxorubicin
Neurotensin NTR1, NTR2, NTR3Small cell lung cancer, neuroblastoma,
pancreatic and colonic cancer
Radioisotopes
Substance PNK1 receptorGlial tumors Radioisotopes
Neuropeptide YY1–Y6Breast carcinomasRadioisotopes