CD274 and neoplasm: It has been shown recently that the COX2/PGE2 pathway is involved in the regulation of immune checkpoints by influencing the programmed cell death ligand 1 (PD-L1) expression in tumor-infiltrating bone marrow derived myeloid cells, primarily MDSC and macrophages, and that the inhibition of PGE2 formation is able to attenuate the tumor induced PD-L1 expression [60].