Th17 cells can act as a source of tumor-induced FOXP3+ cells, as it was shown by Downs-Canner et al. In addition to natural Treg and induced Treg cells formed from naïve precursors, suppressive IL-17A+ FOXP3+ and ex-Th17 FOXP3+ cells are converted from IL-17A+ FOXP3− cells in tumor-bearing mice [204]. This evidence concerns the gene IL17A and neoplasm.