The metabolic pathways of L-arginine (L-Arg) in TAMs highlight these contrasting roles: M1 macrophages produce nitric oxide (NO) via inducible nitric oxide synthase (iNOS), mediating cytotoxic effects [3], while M2 macrophages utilize L-Arg to generate polyamines via arginase-1-mediated metabolism, facilitating tumor growth and suppressing immune response [4]. Here, NOS2 is linked to neoplasm.