Previously, Liu et al. [34] also demonstrated the role of MDSCs in murine breast tumor growth, where the use of Agaricus blazei Murill polysaccharide (pAbM) inhibited tumor growth in at least two ways: by increasing the production of inducible nitric oxide synthase (iNOS) and arginase-1 from Gr-1+ CD11b+ monocytic-like MDSCs and by inhibiting the conversion of CD4+CD25− T-cells into CD4+ Foxp3+ CD25+ regulatory T-cells (Tregs). This evidence concerns the gene NOS2 and neoplasm.