IL17A and neoplasm: While IL-17AnegFoxp3neg and IL-17AnegFoxp3+ Treg cells do not affect tumour progression when compared with control tumour-bearing mice (Fig. 3c), both subsets of IL-17A-producing Foxp3+ and Foxp3neg cells enhance tumour progression compared with IL-17AnegFoxp3+ Treg cells (Fig. 3c).