Consistently, the infiltration of effector Treg cells into tumor cells indicates poor prognosis of overall survival (OS) [87, 112] and FOXP3 is overexpressed in pancreatic [113], prostate [114] and gastric [115] cancers by suppressing antitumor immunity [116] and inducing effector CD4+ T cell death by activation of proapoptotic protein Bad and Bim [101]. Here, FOXP3 is linked to cancer.