CD4 and neoplasm: Alternatively, studies in a murine ovarian cancer model have shown that tumor-derived TGFβ1 can induce PD-L1 expression on DC that suppress T cell proliferation [82], and in patients with highly aggressive triple negative breast cancer, TGFβ1 has been shown to induce regulatory plasmacytoid DC that exhibit diminished type I IFN production and that promote expansion of CD4+ Tregs [83,84].