Fig. 1

Metabolic competition between tumor cells and immune cells. The availability of nutrients for metabolic processes is fundamental for cell survival, along with tumor cells and immune cells are no exception. Competitive uptake of nutrients by tumor cells in the tumor microenvironment may occur at all stages of immune cell life. Metabolite paucity tilts the energy balance in favour of the tumor cells (the negative direction), which in turn leads to further dysfunction of immune cells (such as naïve T cells, B cells, natural killer cells, macrophages, neutrophils, and dendritic cells, etc.)