However, so far these trials only showed very limited therapeutic benefit.6 It has emerged that, although TRAIL is capable of inducing apoptosis in many cancer cell lines in vitro and in vivo, about 50% of cancer cell lines and the majority of primary tumor cells are TRAIL resistant.7 The limited success of clinical trials conducted so far is likely to be attributable to this fact. The gene discussed is TNFSF10; the disease is cancer.