ARG1 and neoplasm: Besides, the L-Nor could suppress the overexpression of Arg-1 in M2 macrophages, which interfered with the balance of arginine metabolism and reversed the immunosuppressive tumor microenvironment (ITM) via increasing the ratios of M1 macrophages and CD8+ T cells, finally resulting in the enhanced antitumor immune responses and tumor metastasis inhibition.1099