GLS and glioblastoma: Interestingly, although no significant differential expression of the total GLS transcripts was observed among different grades of astrocytoma compared to NN, a significant GLSiso2 (GAC) hyperexpression was observed in all grades of astrocytoma when compared to NN (p < 0.0001 Kruskal–Wallis test, and p < 0.001 Dunn test), with the highest expression levels detected in a set of GBM samples (Fig. 1a).