CD274 and neoplasm: The tumor-induced PGE2 due to overexpression of PGE2 synthase 1 and reduction of PGE2 degrading enzyme 15-hydroxyprostaglandin dehydrogenase induces PD-L1 expression in bone marrow-derived cells, macrophages, and myeloid-derived suppressor cells (MDSCs; Prima et al., 2017).