TSPO and central nervous system cancer: The tracer targeting TSPO suggests an association between the TSPO expression level and isocitrate dehydrogenase (IDH) mutation [39,40], which is associated with glioma prognosis, furthermore, the SPECT targeting TSPO has the potential to predict recurrence of HG before the discovery of a recurrence as an enhanced lesion with standard contrasted magnetic resonance imaging [22].