CD4 and neoplasm: The combination therapy of cisplatin (CDDP) and metformin, cisplatin/polystyrene-polymetformin (HA-CDDP/PMet) dual-prodrug co-assembled nanoparticles, in Lewis lung carcinoma (LLC) injected C57/BL6 mice, resulted in tumor cell apoptosis associated with increased CD4+ and CD8+ T cells, a concomitant decrease in Tregs with enhanced expression of the cytokines IFN-γ and TNF-α [84].