CD8A and neoplasm: -Conversion of dietary arginine into nitric oxide and the subsequent formation of peroxynitrite upon reaction with superoxide radicals. -Increased MSDCs-mediated suppressive activity on T-cells. -Promoted tumor progressions by rendering T-cell unresponsive due to aberrant nitration of the T-cell receptor and CD8+ molecules in the presence of excessive amounts of peroxynitrite.