What about α_vβ₃ integrins in molecular imaging in oncology?

Non-invasive investigation of integrin expression is an interesting approach in nuclear medicine department. Indeed, integrins are overexpressed in a wide array of diseases, including tumor neoangiogenesis, cardiovascular pathologies, immune dysfunction, etc. Different targets have been identified in order to be detected and quantified for angiogenesis and vascular remodeling, among them VEGF, matrix metalloproteases, and integrins (α_vβ₃, but also α₅ß₁ and α_vβ₆). Their targeting appears of great interest either for early diagnosis, aggressiveness staging of the disease or for selection of responders to new-targeted therapies. Thus, α_vβ₃ is a biomarker of angiogenesis that specifically binds to RGD containing peptides. Many different strategies were attempted to develop RGD peptides for single photon emission tomography (SPECT) and positron emission tomography (PET) imaging. This review is mainly focused on α_vβ₃-targeting in oncology. We will present an overview of the tracers mostly used on nuclear imaging techniques, those in clinical trials, the recent development concerning the ¹⁸F-labeling strategies, the ⁶⁸Ga-complex chemistry and different approaches of therapy.