TNFSF10 and cancer: Overall, our results show that IFNα-upregulated TRAIL protein accumulates intracellularly and is not secreted in MCF7, BT549 or A549 cancer cells, and since this accumulation was also observed in BT549 cells (where TRAIL is not regulated by cluster enhancers), our results show that intracellular TRAIL protein accumulation is independent of TRAIL transcript upregulation by enhancer clusters.