There is no consensus yet for demonstrating and quantifying PD-L1 expression in PDAC, although the expression rate of PD-L1 in tumour cells is regarded as ~4–60%; however, there is no clear threshold to define PD-L1 positivity.10,34 In this study, we defined PD-L1-positive cases as the ones in which IHC-stained cells were 1% or more of all tumour cells; the group of PD-L1-positive cases is correlated with vascular invasion, histological type, and lymph node metastasis, although the reports have not been consistent. This evidence concerns the gene CD274 and neoplasm.