FOXO1 and neoplasm: Immunophenotyping shows that the frequency of tumor-infiltrating Tregs was not increased in Foxo1fl/flCD4Cre+ mice in comparison to Foxo1fl/flCD4Cre− mice with Zn supplementation (Figure 5G), suggesting that FOXO1 is essential for Zn-mediated Foxp3 Treg function in promoting tumor growth.