TGFB1 and neoplasm: TGF-β produced in the tumor milieu either by the tumor cells or the myeloid cells[1] can cause the proliferation of CD4+CD25+ Treg cells[1] or the conversion of CD4+CD25- into CD4+CD25+ Treg cells[12,13], a reason that in human and murine tumors, increase of CD4+CD25+ T cells has been associated with the reduction of CD4+CD25- T cells[21,22].