To explore the transportation function of GC-derived exosomes to other cancer cells, B-EXO and B KO-EXO were stained with fluorescent PD-L1 antibody and incubated with GC cell line MGC-803, and the exosomal PD-L1 was shown to be transported into target GC cells (Fig. 6a). This evidence concerns the gene CD274 and gastric cancer.