Central to this regulatory network are vital enzymes such as glutaminase (GLS), glutamine synthetase (GS), and glutamine transporters (SLC1A5, also known as ASCT2, etc.), whose activities are finely modulated by various oncogenic and tumor suppressive pathways involving primary metabolites, such as glutamate (Glu), α-ketoglutarate (α-KG), and lactate. The gene discussed is GLUL; the disease is neoplasm.