An Overview of Radiolabeled RGD Peptides for Theranostic Applications.

Angiogenesis phenomenon, as a highly affecting factor on the growth and spread of cancer cells, depends on specific molecular interactions between components of the extracellular matrix and vascular cells. αv integrin acts as a cell adhesive molecule involved in tumor invasion and angiogenesis. Among the various combinations of integrin subunits expressed on the surface of cells, αβ integrin has a particularly interesting expression pattern during angiogenesis. The αβ integrin is a vital receptor affecting tumor growth, tumor invasiveness, metastasis, and angiogenesis overexpressed on various human tumors, leading to the development of different theranostics probes and radiopharmaceuticals. The αβ integrin can recognize several extracellular matrix molecules in the base of the RGD adhesive sequence. This review provides an overview of the status, trends and future of the most studied αβ integrin-binding ligand, RGD tripeptides, labeled with various radioisotopes. An overview of the pre-clinical models for radiolabeled RGD peptides and clinical aspects of the RGD- based radiopharmaceuticals is provided with some new considerations and ways forward.