GLUL and cancer: From a metabolic point of view, since MAMs are known to promote metastasis formation through signaling and metabolic conditioning of the pre‐metastatic niche to prepare the microenvironment for cancer cells survival and proliferation (Qian et al, 2015; Celus et al, 2017; Prenen & Mazzone, 2019), it can be speculated that GS expression in MAMs might be fundamental to supply glutamine, which is probably a limiting metabolite in the delicate step of metastatic growth.