CD8A and neoplasm: Hyaluronan is the main component of the ECM, and its precursor is synthesized by the HBP, and L-DON inhibits glutamine-fructose aminotransferase 1 (GFPT1), the rate-limiting enzyme in the HBP, resulting in decreased hyaluronan synthesis, affecting the mechanical properties of the ECM in the TME and enhancing the infiltration of CD8+T cells and the anti-tumor immune response [120].