IFNA1 and cancer: Moreover, we observed in MCF7 and A549 cells that pretreatment with BET inhibitors 3 h prior to IFNα stimulation dramatically decreased TRAIL mRNA upregulation by IFNα at 6 h, an effect we did not observe in BT549 cancer cells, which lack an enhancer cluster for TRAIL (Figure 2D), suggesting that a functional enhancer cluster is necessary for the increase in TRAIL gene expression driven by IFNα.