Gene expression profiling has shown an upregulation of the glutamine importer ASCT2 (SLC1A5) compared to low grade gliomas, and glutamine deprivation has slowed GBM tumor growth in some in vitro studies (Hassanein et al., 2013; Obara-Michlewska and Szeliga, 2020). Here, SLC1A5 is linked to central nervous system cancer.