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29 May 2008
New York, USA
Attacking a virus to tackle brain tumour
Experts have suggested a new way to tackle particularly tenacious brain tumours known as glioblastomas by attacking a virus often found in these cancers.
The technique which may halt their growth could provide an alternative to current surgical treatments for glioblastoma, which, because of the tumours position deep in the brain, carry a significant risk of brain damage, Nature magazine said.
It may help doctors pursue their preferred tactic of allowing the body’s own immune system to attack cancer cells, systematically eradicating them from the brain tissue without harming nearby healthy cells.
Until now it has been impossible for the immune system to distinguish brain tumour cells from healthy cells as they often have the same identifying marker proteins–called antigens–and because brain tumours often suppress immune function.
In the new study, Nature reports, oncologist Duane Mitchell at Duke University Medical Centre and colleagues build on previous research showing the consistent presence of cytomegalovirus, a type of herpesvirus, in glioblastoma cells but not in surrounding healthy tissue.
Roughly 50 to 80% of healthy people in the United States are infected with cytomegalovirus, although in healthy people it remains latent. Virus particles multiply to high numbers only in those with compromised immune systems and the team wondered they could halt the cancer by guiding the immune system to attack the unique antigens of the virus in glioblastoma cells.
The team, the report says, took white blood cells from 21 patients, exposed them to parts of the virus, and injected the cells back into the patients. Their preliminary results suggest that this technique is safe and effective. “Because the immune system kills both the virus and the cell it resides in, we are hoping that we will be able use this vaccine to kill the tumour cells that standard therapy can’t reach”, explains Mitchell.
Mitchell and his colleagues will unveil their findings on 1 June at a meeting of the American Society of Clinical Oncology in Chicago
Although the results are preliminary, tumour progression was delayed by more than a year on average–and several patients had no sign of tumour growth after two years.