TNFSF10 and cancer: Recent reports on first clinical trials with TRAIL and other TRAIL-R agonists showed, on the one hand, that these biotherapeutics were well tolerated but, on the other, that the clinical activity they exerted, even when combined with standard chemotherapy, was rather limited.6 Cancer cell resistance to TRAIL-induced apoptosis is likely to be a significant factor in this outcome, indicating that a TRAIL-comprising therapy will only be effective when a potent TRAIL sensitizer is applied in combination with a TRAIL-R agonist.