The therapeutic use of viruses against cancer has been revived during the last two decades. Oncolytic viruses replicate and spread inside tumors, amplifying their cytotoxicity and simultaneously reversing the tumor immune suppression. Among different viruses, recombinant adenoviruses designed to replicate selectively in tumor cells have been clinically tested by intratumoral or systemic administration. Limited efficacy has been associated to poor tumor targeting, intratumoral spread, and virocentric immune responses. A deeper understanding of these three barriers will be required to design more effective oncolytic adenoviruses that, alone or combined with chemotherapy or immunotherapy, may become tools for oncologists.
Keywords: adenovirus; cancer; oncolytic; virotherapy.