TGFB1 and cancer: Specifically, recombinant OVs can circumvent many of the tumour’s mechanisms of immune escape (e.g. by enhancing type I IFN signalling, upregulating major histocompatibility complex (MHC) class I expression on cancer cells [23], targeting enhanced transforming growth factor beta (TGF-β)/Wnt/β-catenin signalling and its negative impact upon antigen presentation [24] or by delivering inhibitors of active immunosuppressive pathways in the TME e.g. prostaglandin E2 (PGE2) [25] or adenosine A2a receptors (A2ARs).