STAT4 and neoplasm: To determine the functional impact of STAT4 SUMOylation on macrophages against tumor development, BMDMs were first transfected with a Stat4 siRNA within the 3′-untranslated region to knock down the endogenous Stat4 (Supplemental Figure 5B), and then transduced with Stat4-WT or Stat4-K350R adenoviruses, followed by coculturing with CD8+ T cells.