KRT17 and neoplasm: However, emerging evidence from retrospective studies suggests circulating tumor DNA (ctDNA), a proxy for tumor burden, and keratin 17 (K17) expression in tumor cells, a validated biomarker of the most aggressive molecular subtype of PDAC, may have a role as prognostic biomarkers.9,10,11,12,13,14 We aimed to study whether dynamic changes in K17 and ctDNA expression were prognostic for resectable PDAC treated with perioperative mFOLFIRINOX in a prospective controlled trial.