AKT1 and neoplasm: PD-L1 secreted from tumor cells into the tumor microenvironment has been found to decrease CD8+ T cell activation.29 Therefore, we assessed whether secreted PD-L1 decreased CD8+ T cell activation by measuring p-AKT expression because p-AKT is highly associated with CD8+ T cell activation and proliferation.30 The TCM was prepared by isolating TC-1 culture media after PD-L1 silencing using PLGA (PD-L1 siRNA)-NPs.