Finally, since multiple soluble mediators, such as TNF-α, IFN-γ, IL-1β, IL-17, and IL-27, induce PD-L1 expression on tumor cells [30,31], it may be reasonable to raise the question of whether the expression of certain mediators among them is downregulated by NDRG2 expression. The gene discussed is NDRG2; the disease is neoplasm.