Most importantly, SA-4-1BBL also modulates regulatory immunity by reversing tumor induced clonal anergy, rendering T effector (Teff) cells resistant to suppression by CD4+CD25+FoxP3+ T regulatory (Treg) cells [7], and inhibiting the conversion of Teff cells into Treg cells through the production of IFN-γ [10]. This evidence concerns the gene FOXP3 and neoplasm.