RORC and neoplasm: The percentage of tumour-associated Foxp3+ cells (Fig. 2a) and Foxp3 expression (Supplementary Fig. 2a) is significantly reduced in RORγ−/− ID8 tumour-bearing mice compared with controls (n=5 per group), suggesting that Th17 cell transdifferentiation serves as an important pathway of Treg cell emergence in the tumour microvenvironment.