TNF and neoplasm: In vitro studies have also shown that synergy between the Th1 cytokines IFN-γ and TNF-α, which have increased production after DC vaccination, and trastuzumab induces PD-L1 expression and MHC class I upregulation on HER2- overexpressing cells in vitro, facilitating CD8+ T cell recognition of tumor cells (Datta et al., 2015d; Figure 2).