Finally, an increase in plastic Foxp3+ Th17 cells infiltrating the tumour micorenvironment of ovarian cancer patients and the tumour-associated induction of Foxp3 expression in human IL-17A-producing ovarian cancer tumour-associated lymphocytes (TALs) validates the concept that inhibiting Th17-to-Treg cell conversion may serve as a valuable targeting strategy in tumour immunotherapy. The gene discussed is IL17A; the disease is ovarian cancer.