Effector T cells and glutamine-dependent tumor cells within tumors both rely on glutamine, indicating a competition for glutamine metabolism in the tumor microenvironment.268 Glutamine is crucial for fueling mTORC1 activity in T cells, a process essential for their differentiation into effector T cells by providing the required energy.269 Restricting external glutamine can prompt the differentiation of CD4+ naive T cells into Treg cells, even in conditions conducive to generating other T cell subsets. The gene discussed is CD4; the disease is neoplasm.