PCSK2 and pancreatic adenocarcinoma: Subsequently, the analysis of the expression of these genes in PAADs indicated that there were substantial differences in the expression of CHGA, CHGB, PCSK2, PCSK1N, DLGAP1 and DLGAP3 genes in PAAD with and without lymphatic metastasis, and their expressions were down-regulated in the lymphatic metastasis group (Fig. 4).