Several groups have employed viral vectors for TRAIL gene therapy and achieved efficient suppression of xenograft tumor growth in various cancer types.12, 13, 14 However, there are safety concerns inherent to viral gene therapy, including risk of immunogenicity,15 tumorigenicity,16 and cytotoxicity,17 as well as the practical limitations of limited cargo carrying capacity and manufacturing challenges. This evidence concerns the gene TNFSF10 and cancer.