PDCD1 and colonic neoplasm: Prodeus et al. discover that MP7 (a short synthetic anti-PD-1 DNA aptamer) specifically binds to the extracellular domain of PD-1, competitively antagonizes the direct binding between PD-1 and PD-L1 molecules, functionally blocking PD-L1-mediated immune suppression signals and ultimately inhibiting the growth of colon cancer [434].