Prevalence of FOXP3+ Regulatory T Cells Increases During the Progression of Pancreatic Ductal Adenocarcinoma and Its Premalignant Lesions

PURPOSE: Antitumor immune response changes drastically during the progression of cancers. Established cancers often escape from the host immune system, although specific immune surveillance operates in the early stages of tumorigenesis in murine models. CD4+CD25+ regulatory T cells (TR) play a central role in self-tolerance and suppress effective antitumor immune responses. The aim of this study was to investigate the clinical significance and roles of TR in the progression and multistep carcinogenesis of pancreatic ductal adenocarcinoma. EXPERIMENTAL DESIGN: We raised anti-FOXP3 antibodies and used them in immunohistochemical studies of the prevalence of FOXP3+CD4+CD25+ TR in the CD4+ T cells, which…