Virus Cures Deadly Human Brain Cancer in Mice

A cancer-fighting virus has eliminated malignant brain tumors and prolonged survival in mice with a single injection.

Reporting in the journal Cancer Research, Canadian scientists from Calgary and London, Ontario have shown for the first time that myxoma virus, a poxvirus, kills human brain tumors in mice.

“We’re extremely encouraged by these results and the apparent cure seen in the mice treated with the active virus compared to untreated mice or those injected with inactivated virus,” says researcher Grant McFadden of Robarts Research Institute in London.

For the brain tumor experiments, McFadden teamed up with Dr. Peter Forsyth of the University of Calgary, a professor in the departments of oncology, and biochemistry & molecular biology, who has developed a mouse model with human gliomas, a malignant form of brain tumor. Over the past two years, their laboratories have tested the virus against experimental models of human malignant tumors, both in cell culture and in living animals. Injecting the tumor with the virus was not only well-tolerated – with only minimal inflammation at the site of the inoculation—but 92 per cent of the 13 mice treated were alive and apparently “cured” when the experiment was finished (after more than 130 days).

“Those animals continued to show a selective and long-lived myxoma virus infection in the tumors themselves but that infection did not spread and harm the animal,” says Dr. Forsyth, director, Clark H. Smith Integrative Brain Tumour Research Centre. “This and other factors suggest that myxoma virus warrants further investigation as a potential treatment for malignant brain tumors in people.”

The University of Ottawa also played a major role: Dr. John Bell initiated the Canadian Oncolytic Virus Consortium, a program funded by The Terry Fox Foundation, to study various viruses with the potential to treat cancer. In 2004, Dr. Bell brought together the teams from London and Calgary to initiate the study reported in Cancer Research.

McFadden and Forsyth are now planning to test the virus as a treatment for a deadly melanoma that is known to spread to the lung. They will be able to tag the virus with a fluorescent protein and track its progress in mice as it attacks the metastasized tumor cells.