Usefulness of endoscopic biopsy using FOXP3+ Treg up‐regulation in the duodenal papilla in the differential diagnosis between autoimmune pancreatitis and pancreatic cancer

Background and study aims Expression of the forkhead/winged helix family of transcription factor P3+ regulatory T cells (FOXP3+ Treg), a master gene of regulatory T cells (Treg) is observed in patients with autoimmune pancreatitis (AIP). We investigated the usefulness of detection of FOXP3+ Treg in the main duodenal papilla for differential diagnosis between AIP and pancreatic cancer (Pca).