Therefore, to assess the potential of COX-2 inhibition plus anti-PD-L1 antibody as combination therapy, we first confirmed COX2 mRNA expression and PGE2 upregulation in canine cancers, and then examined the immunosuppressive effects of PGE2 in cultures of canine peripheral blood mononuclear cells (PBMCs). The gene discussed is PTGS2; the disease is cancer.