Lux et al. (2019) examined the expression of PD-L1 in blood samples and showed that the survival time of PD-L1-positive patients was significantly lower than that of PD-L1-negative patients. Therefore, the expression of PD-L1 in exosomes has profound significance for the prognosis of pancreatic cancer. However, since exosome PD-L1 expression in CP patients is higher than that in PDAC patients, exosome PD-L1 may not be suitable as a diagnostic indicator for pancreatic cancer (Lux et al., 2019). This evidence concerns the gene CD274 and pancreatic neoplasm.