IL6 and neoplasm: Once in the tumor, MDSCs produce immunosuppressive cytokines like IL-6, VEGF, and arginase-1, which dampen T cell responses and promote tumor growth.93, 94, 95 The presence of MDSCs in the TME is associated with poor clinical outcomes, as they not only suppress anti-tumor immunity but also foster an environment that supports tumor progression, metastasis, and resistance to therapies.96