Scientists claim that some kinds of live mutated viruses can cure tumors in animals and humans.
Scientists led by Moira Brown from the University of Glasgow treated a patient with an aggressive form of brain cancer after finding the method safe in animals, the New Scientist reported.
A mutation of the herpes virus was injected into the patient who had been given only four months to live in 1997. But, eight years later he is still alive and his tumor has gone, the report said.
They used the same method on another patient who took part in the trial and got similar success. The patient is still alive and a further 10 cancer sufferers were able to live months longer than expected, it said.
Brown and his team are now going beyond creating a simple mutant and "arming" viruses to make cancer cells commit suicide or to make the body's own immune system turn on them.
This would seem the perfect biological weapon against cancer because viruses excel at killing cells, which is the goal of any cancer therapy.
Viruses engineered to target only cancer cells would be a "precision weapon" because they can take out thousands of cancerous cells per every healthy cell they kill. Chemotherapy drugs only destroy around six cancerous cells for every healthy cell.
No oncolytic viruses, meaning those that cause cancer cells to burst, have yet been approved. The technique appears to be safe with only flu-like symptoms reported as the only adverse effects seen in trials so far.