“…Forkhead box P3 (FOXP3)-expressing Treg cells are a potent mediator of peripheral immune tolerance and suppress a wide range of immune cells, including CD4 + and CD8 + T cells, NK cells, NKT cells, B cells, and antigen presenting cells, through suppression of target cell activation, proliferation, and effector functions (Shevach, 2009;Sakaguchi et al, 2010;Jiang and Shapiro, 2014). Infiltration of Treg cells into breast cancers has been observed in numerous studies, and the number of Treg cells in the tumor site has been shown to be associated with a worse prognosis (Bates et al, 2006;Bohling and Allison, 2008;Ohara et al, 2009).…”