TNF and breast cancer: The significant decrease in degranulation of NK cells infiltrating IFN-γ + TNF-α-treated BC spheroids compared to untreated spheroids was associated with the significant upregulation of MHC-I assessed in IFN-γ + TNF-α-treated BC spheroids compared to untreated spheroids (Fig. 6), thus responsible for negative signals outweighing activating ones [32].