PD-1 Expression by Lymph Node and Intratumoral Regulatory T Cells Is Associated with Lymph Node Metastasis in Pancreatic Cancer. - Seifert, Adrian M.; Eymer, Annabel; Heiduk, Max; Wehner, Rebekka; Tunger, Antje; von Renesse, Janusz; Decker, Rahel; Aust, Daniela E.; Welsch, Thilo; Reissfelder, Christoph; Weitz, Jürgen; Schmitz, Marc; et al. (Cancers, 2020)