PD-L1-EVs also contribute to the establishment of metastatic niches; for example, M2 macrophages in ovarian cancer appear in the peritoneal cavity even before tumor cells arrive, where they target carnitine palmitoyl-transferase 1 A expression in T cells within the peritoneal cavity through the PD-L1-EVs they release. This evidence concerns the gene CD274 and ovarian cancer.