“…To date, several immuno-PET imaging tracers have been designed to target glioblastoma and have already proven successful in detecting gliomas in multiple preclinical models. These tracers target membrane proteins whose expression is altered in glioblastoma (including the EGFR, DLL4, EPHA2, CD47, AC133 antigen, and MT1-MMP) [ 94 , 95 , 96 , 97 , 98 , 99 , 100 , 101 , 106 , 107 ]: several components of the tumor microenvironment including vessels, macrophages, and extracellular matrix proteins [ 104 , 105 , 108 , 109 , 110 , 114 ]. Notably, [ 89 Zr]Zr-DFO-fresolimumab, an immuno-PET tracer based on a monoclonal antibody that can neutralize all mammalian isoforms of TGF-β was assayed in humans, penetrated recurrent high-grade gliomas but did not result in clinical benefit [ 109 ].…”