Virotherapy is an experimental form of cancer treatment using biotechnology to convert viruses into cancer-fighting agents by reprogramming viruses to attack cancerous cells, while healthy cells remained relatively undamaged. Usually the viruses used are herpes simplex virus or Adenoviruses.
It uses viruses as treatment against various diseases, most commonly as a vector used to specifically target cells and DNA in particular. It is not a new idea - as early as the 1950s doctors were noticing that cancer patients who suffered a non-related viral infection, or who had been vaccinated recently, showed signs of improvement: this has been largely attributed to the production of interferon and tumour necrosis factors in response to viral infection, but oncolytic viruses are being designed that selectively target and lyse only cancerous cells.
In the 1940s and 1950s, studies were conducted in animal models to evaluate the use of viruses in the treatment of tumors. In 1956 some of the earliest human clinical trials with oncolytic viruses for the treatment of advanced-stage cervical cancer were started. However, for several years research in this field was delayed due to the inadequate technology available. Research has now started to move forward more quickly in finding ways to use viruses therapeutically.