To evaluate whether four important candidate genes in stromal cells, C9orf89, MAGI2, MLPH, and RHBDD2, are associated with prognosis, immunohistochemical staining of C9orf89, MAGI2, MLPH, or RHBDD2 in pancreatic ductal carcinoma surgical resection samples without neoadjuvant chemotherapy (n = 60) was conducted (Supplementary Data 2). Here, CARD19 is linked to pancreatic ductal adenocarcinoma.