This study investigated the role of four previously established fibroblast markers—FAP, PDGFR, periostin, and SMA—in a large study population of 321 patients with pancreatic ductal adenocarcinoma who underwent a surgical resection with a curative intension in one of the PANCALYZE study centers. The gene discussed is POSTN; the disease is pancreatic ductal adenocarcinoma.