Intriguingly, gemcitabine has been shown by us to act as a DNA methyltransferase inhibitor, reactivating silenced genes in mesothelioma cells [174], and as such the observed responses to gemcitabine on PD-L1 expression changes may reflect an epigenetic priming event, although functional studies will be required to delineate this. Here, CD274 is linked to mesothelioma.