Common human virus may help treat deadliest form of brain tumours

November 14th, 2007 - 2:41 am ICT by admin  
Researchers at Duke’s Preston Robert Tisch Brain Tumor Center, who conducted the study, said that the finding is an important step in developing a vaccine that can attack the tumours by enlisting the help of the body’s immune system.

Duane Mitchell, M.D., Ph.D., a brain cancer researcher and lead author of the study, said that human cytomegalovirus (HCMV), which infects 50 percent to 90 percent of people at some point during their lives, is active in more than 90 percent of patients diagnosed with glioblastoma multiforme, the most deadly type of malignant brain tumour.

“We don’t know if the virus plays a part in the growth of the brain tumours or whether the presence of the brain tumours leads to a reactivation of the virus,” Mitchell said.

“But we do know that the virus has the potential to affect the growth and invasiveness of cancer cells. So if we can target it, we may be able to empower the body’s immune system to fight infected tumor cells and destroy the cancer,” he added.

According to the researchers, a vaccine targeting HCMV likely would be administered to patients following conventional chemotherapy.

Mitchell said that the immune system’s recovery from chemotherapy is marked by a regenerative burst of new immune cells, and the vaccine would take advantage of this reaction to effect an even stronger immune response to the virus.

In healthy people with fully functional immune systems, the initial HCMV infection can be symptom-free or it can be associated with mild flulike symptoms.

After infection, the virus becomes dormant and stays that way for the life of the infected person. But in people with weakened immune systems - such as AIDS patients or those undergoing bone marrow transplant - HCMV can become reactivated and cause more severe illnesses, such as pneumonia.

The association between HCMV and brain tumours was first demonstrated in 2002 by researchers at the University of Alabama - Birmingham, but their results had not been repeated despite several attempts.

“We not only confirmed the virus’ association with the tumours but also saw that patients with glioblastoma multiforme had detectable virus in their bloodstreams, where the comparative group did not,” Mitchell said.

“This association may help us assess the success of vaccine treatment, since we will be better able to monitor response in patients, even after their tumours have been removed,” he added.

On the basis of the findings of this study, the authors have developed a vaccine that targets HCMV and are conducting a clinical trial to assess the vaccine’s safety and its effectiveness at building immunity to HCMV in patients with brain tumours.

In the trial, which will complete enrolment this year, the vaccine is given monthly to cancer patients in conjunction with chemotherapy for as long as their tumours remain stable.

“We’re encouraged by the early results we’re seeing in the clinical trial and we’re pleased that the initial study enabled us to proceed with testing this vaccine in patients,” Mitchell said.

“Because HCMV is present in such a large number of glioblastoma multiforme patients, the development of an effective treatment that targets the virus could have significant implications for this deadly disease,” he added.

The study will be published in the February 2008 print issue of the journal Neuro-Oncology. The study was published early online on October 19, 2007. (ANI)

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