STAT3 activation antagonizes expression of anti-tumor T helper 1 cytokines (such as IL-12 and IFN-γ), mediates T regulatory cell expansion in tumors, and is required for the immunosuppressive effects of MDSCs and tumor-associated macrophages, as well as for the development of tumor-promoting TH17 T cells (64). The gene discussed is IFNG; the disease is neoplasm.