PDCD1 and neoplasm: Their results indicate that while TUSC2 alone significantly reduced tumor growth and prolonged survival compared with anti-PD-1 only, when combined, this effect was significantly enhanced and correlated with an increase in circulating natural killer (NK) cells and CD8+ T cells and a decrease in regulatory T cells (Tregs), myeloid-derived suppressor cells (MDSCs), and T cell checkpoint receptors PD-1, CTLA-4, and TIM-3 [141].