Thus, in situ microscopy results can serve as the basis for interpretation of in vivo PET/CT/MRI images and confirm that the increased levels of radiotracer accumulation in intracerebral 9L gliomas and in certain normal brain structures are mediated by increased SIRT2 expression-activity levels, as compared to other brain structures expressing lower levels of SIRT2. Here, SIRT2 is linked to central nervous system cancer.