Previous murine and in vivo human studies in intrinsic CNS tumors such as high-grade glioma have combined advanced methods such as immunomagnetic cell sorting (MACS) after in vivo radiotracer injection45,46 (scRadiotracing) and 3D histology to interrogate TSPO-expressing cell populations within the tumor microenvironment, demonstrating, for example, higher TSPO binding within neoplastic tumor cells compared to tumor-associated microglia/macrophages. This evidence concerns the gene TSPO and central nervous system cancer.