Engineered A4 virus carrying the TRAIL gene expresses TRAIL protein on the viral surface by linking to the Leu zipper of capsid protein IX (Wang et al., 2016), which can bind to its receptor TRAILR1 (also known as DR4) or TRAILR2 (also known as DR5) to specifically induce apoptosis in cancer cells (Johnstone et al., 2008). The gene discussed is TNFSF10; the disease is cancer.