FOXP3 and melanoma: An accumulation of FoxP3+ Tregs and, in particular, a higher Treg : T effector cell (Teff) ratio within tumor tissue is associated with worse prognoses in many cancers, including ovarian cancer [17,18], pancreatic ductal adenocarcinoma [19,20], lung cancer [21], glioblastoma [22], non-Hodgkin’s lymphoma [23], melanoma and other malignancies [24,25].