PDCD1 and neoplasm: siRNA for PD-1 (siPD-1) was reported to be encapsulated in noncationic soft polyphenol nanocapsules, amphiphilic triblock polymers, and dendrimer-entrapped gold nanoparticles to increase its tumor tissue penetration 43, 44 and avoid its degradation through facilitating endosomal escape of internalized siPD-1 45.