CD274 and neoplasm: Furthermore, IHC detection results of the positive expression of immune cell-associated protein PD-L1 in the tumor tissues of mice uncovered that the expression of PD-L1-positive protein was increased in the TAM-EV-treated mice compared with PBS-treated mice; the expression of PD-L1-positive protein was decreased in the TAM-In-miR-29a-3p-EV-treated mice compared with TAM-EV-treated mice (Figure 7F).