Cancer gene therapy with oncolytic adenoviruses

Metastatic cancer remains diffi cult to treat effectively and treatments are in most cases not curative despite sig-nifi cant side effects. Novel, targeted approaches such as gene therapy hold promise for the treatment of various tu-mor types. Among the most promising cancer gene therapy approaches are oncolytic adenoviruses, which are able to infect, replicate in and lyse tumor cells. Recent data from clinical trials with these vectors have shown that they are safe. However, antitumor effi cacy needs to be improved to make oncolytic adenoviruses a viable treatment alterna-tive for cancer patients. This review focuses on targeting strategies to improve tumor cell transduction and cancer cell selective replication. Strategies to improve antitumor effi cacy by arming the virus with therapeutic transgenes are also discussed. Furthermore, an overview of the most important clinical approaches with oncolytic adenoviruses is given. Key words: cancer gene therapy, clinical trials, oncolytic adenoviru