MICA and neoplasm: A variety of tumour-derived soluble factors has been linked to the building of complex immunosuppressive networks, including VEGF, IL-10, TGF-β, prostaglandin E2, soluble ligands (soluble MHC class I polypeptide-related sequence A (MICA), UL16 binding proteins (ULBPs) and decoy receptors, as reminded before, or effector molecules [27].