IFN-alpha is highly expressed in cells of tumour tissues and, through phosphorylated STAT 1, binds to a sequence element of binding to the IRF pathway in vitro and to chromatin in vivo at the CD274 promoter to ultimately activate PD-L1 transcription in addition to IFN-alpha; IL-10, VEGF, and hypoxia are other critical modulators of PD-L1 expression in MDSCs. Here, CD274 is linked to neoplasm.