Tumor detection using folate receptor-targeted imaging agents.
Folate receptors are up-regulated on a variety of human cancers, including cancers of the breast, ovaries, endometrium, lungs, kidneys, colon, brain, and myeloid cells of hematopoietic origin. This over-expression of folate receptors (FR) on cancer tissues can be exploited to target folate-linked imaging and therapeutic agents specifically to FR-expressing tumors, thereby avoiding uptake by most healthy tissues that express few if any FR. Four folate-targeted therapeutic drugs are currently undergoing clinical trials, and several folate-linked chemotherapeutic agents are in late stage preclinical development. However, because not all cancers express FR, and because only FR-expressing cancers respond to FR-targeted therapies, FR-targeted imaging agents have been required to select patients with FR-expressing tumors likely to respond to folate-targeted therapies. This review focuses on recent advances in the use of the vitamin folic acid to target PET agents, gamma-emitters, MRI contrast agents and fluorescent dyes to FR(+) cancers for the purpose of diagnosing and imaging malignant masses with improved specificity and sensitivity.
Sega
Emanuela I
EI
Department of Chemistry, Purdue University, West Lafayette, IN 47907, USA. esega@stanford.edu
Low
Philip S
PS
D000818:Animals; D002352:Carrier Proteins / Q000008:administration & dosage*; D003952:Diagnostic Imaging; D016503:Drug Delivery Systems / Q000379:methods; D058973:Folate Receptors, GPI-Anchored; D005492:Folic Acid / Q000008:administration & dosage*; D006801:Humans; D009369:Neoplasms / Q000175:diagnosis* / Q000188:drug therapy / Q000378:metabolism; D019275:Radiopharmaceuticals; D011956:Receptors, Cell Surface / Q000008:administration & dosage*
D002352:Carrier Proteins; D058973:Folate Receptors, GPI-Anchored; D019275:Radiopharmaceuticals; D011956:Receptors, Cell Surface; D005492:Folic Acid