CD274 and neoplasm: The molecular mechanisms involved in the immune modulatory effects of M2 macrophages have not been completely elucidated, but it has been proposed that these macrophages suppress the anti-tumor immune response through expression of the inhibitory molecule programmed death ligand 1 (PD-L1) and secretion of the immunosuppressive mediator Interleukin-10 (IL-10) [4].