L-Arginine supplementation inhibits the growth of breast cancer by enhancing innate and adaptive immune responses mediated by suppression of MDSCs in vivo

L-Arg is involved in many biological activities, including the activation of T cells. In breast cancer patients, L-Arg is depleted by nitric oxide synthase 2 (NOS2) and arginase 1 (ARG-1) produced by myeloid-derived suppressor cells (MDSCs).