CTLA4 and neoplasm: He et al. demonstrated that, at low local levels, IFNγ promotes tumor progression of several murine tumor models, including hepatic, mammary and skin cancer, through increased gene expression of Cd274 (PD-L1), Ctla4 and Foxp3, whereas at higher levels, IFNγ reduces the gene expression of Foxp3 and co-inhibitory molecules (58).