There is also competition between tumor cells and niche cells for limited space and nutrition, such as the competitive absorption of taurine by SLC6A6+ tumor cells and T immune cells [99], the competitive phagocytosis of nutrients and cell debris by Mychigh tumor cells and macrophages [100], and the competitive uptake of glutamine by tumor cells and cDC1 through SLC38A2 [101]. The gene discussed is MPPE1; the disease is neoplasm.