ARG1 and neoplasm: TIPE2 sustains the inhibitory function of MDSCs targeting T cells in tumor-bearing mice, as TIPE2 serves as a crucial molecular switch controlling MDSC functional polarization through conversion between M2 immunosuppressive signature genes like ARG-1 and M1 proinflammatory signatures, such as inducible nitric oxide synthase (iNOS) [53].