However, effective i.v. administration of Ad5-based vectors is hampered by the complex interactions between virus and host proteins, leading to hepatic tropism and immune clearance, and causing the Ad5 vector to be diverted away from the desired tumor targets.25–28 As death receptors are expressed at higher levels on the surfaces of tumor cells than on normal cells, TRAIL has been used to target tumor cells. Here, TNFSF10 is linked to neoplasm.