Future prospects for oncolytic therapy.

Viruses have been engineered to replicate selectively in cancer cells, based on a number of innovative principles. Several of these viruses have entered clinical trials and have proven relatively safe, and have shown evidence of efficacy. However, further research is required to enable these agents to function systemically. This might involve attempts to suppress immune responses to virus antigens, and re-targeting of viruses to favor tumor infection and increased potency. When these barriers are overcome, oncolytic viruses could enter the mainstream of clinical oncology.