To this end, repeated on‐treatment levels of soluble DCN were measured using proximity extension assay in 124 patients enrolled in a prospective, observational clinical study, inviting patients diagnosed with pancreatic or other pancreatobiliary‐type periampullary adenocarcinoma eligible for adjuvant (n = 30) or first‐line palliative (n = 94) chemotherapy. This evidence concerns the gene DCN and periampullary adenocarcinoma.