CD4 and pancreatic neoplasm: Further, in this work, we focused on the role of TCF1 in CD4+ T cells, as they are the main suppressive lymphocyte populations in pancreatic cancer, based on past work by several groups including ours (Daley et al., 2016; Jang et al., 2017; McAllister et al., 2014; Ochi et al., 2012; Zhang et al., 2014).