FOXP3 and neoplasm: In addition, the evidence that regulatory T cells can lose FoxP3 [90], effector T cells can transiently express FoXP3 without acquisition of suppressive functions [91,92] and FoxP3 acts as tumor suppressor gene and it is expressed on tumor cells [93-95] complicates the interpretation of the aforementioned studies in absence of functional and cell-specific analyses.