blood cells

Scientists in the UK have shown how a cancer-killing viral therapy can sneak up on tumours by ‘hitching a ride’ on blood cells.

Up until now, doctors have been concerned about injecting the experimental therapy directly into tumours, as this method makes it difficult to treat tumours deep within the body, such as the liver and pancreas.

Researchers had also feared that antibodies in the blood would neutralise the virus before it reached its target.

"The virus stayed active during treatment and targeted cancer cells without damaging the liver."

A study by the University of Leeds and the Institute of Cancer Research, however, has revealed that reoviruses are shielded from antibodies in the bloodstream.

The study, carried out on ten people, showed that the virus stayed active on its journey through the body and honed in on cancer cells, ignoring healthy tissue.

The study involved 10 patients with advanced bowel cancer who were due to have surgery on tumours that had spread to the liver.

All patients were given up to five doses of the reovirus in the weeks before surgery, as outpatients.

Blood tests carried out shortly after treatment found that the virus stayed active during treatment and targeted cancer cells without damaging the liver.

In the blood, the virus was detected in blood cells, not the liquid blood plasma that all cells float in, meaning it was "hitchhiking", the researchers said.

University of Leeds’ researcher, Professor Alan Melcher, jointly led the study. Melcher said: "It seems that reovirus is even cleverer than we had thought. By piggybacking on blood cells, the virus is managing to hide from the body’s natural immune response and reach its target intact. This could be hugely significant for the uptake of viral therapies like this in clinical practice."

Julie Sharp, senior science information manager at Cancer Research UK, which part-funded the research, commented: "This promising study shows that reovirus can trick the body’s defences to reach and kill cancer cells and suggests that it could be given to patients using a simple injection. We look forward to seeing how this research develops and if this could one day become part of standard cancer treatment."

Image: Reoviruses can sneak up on tumours by riding on blood cells. Photo courtesy of: