TNFRSF9 and neoplasm: In addition, compared to the anti-CD137 agonistic antibody urelumab, either unconjugated or conjugated to MSNs, rhCD137L-MSNs display a stronger capacity to functionally engage CD137, as reflected by enhanced T cell functions and improved tumor control both in vitro (at an equal molar concentration) and in vivo (at an equal mass concentration).