M1-type MDSCs exhibit anti-tumour activities by secreting interleukin-12 (IL-12), tumour necrosis factor (TNF-α) and nitric oxide (NO); whereas M2-polarized MDSCs suppress T lymphocytes-mediated tumour-killing responses through the expression of interleukin-10 (IL-10), transforming growth factor (TGF-β) and arginase17, 18, 19. The gene discussed is TNF; the disease is neoplasm.