Zika virus kills brain tumors like John McCain’s, according to new research.
The mosquito-borne infection is most widely-known for causing birth defects in unborn children, such as microcephaly which stunts brain growth.
However new research by Washington University School of Medicine found it is possible to use the virus to target tumor cells in adult brains.
Scientists believe it could one day be used alongside traditional treatments like chemotherapy and radiation to eradicate whole tumors.
Sen John McCain was diagnosed with a malignant primary brain tumor after being hospitalized for a blood clot behind his eye
Glioblastoma is the most common and deadly forms of brain cancer with patients dying within just two years of diagnosis.
The growth and development of glioblastomas is driven by stem cells that proliferate and give rise to other tumor cells
Stem cells of the cancer are hard to kill because they avoid body’s immune system and are resistant to chemotherapy and radiation.
Killing these cells is vital to prevent new tumors from recurring after the original tumor has been surgically removed.
Dr Milan Chheda said: ‘It is so frustrating to treat a patient as aggressively as we know how, only to see his or her tumor recur a few months later.
WHAT IS GLIOBLASTOMA?
Glioblastoma is the most aggressive tumor that can form in the brain. Patients have a 10 percent chance of surviving five years after their diagnosis.
It is made up of a mass of cells growing in the brain, and in most cases patients have no family history of the disease, according to the American Cancer Society.
The tumor won’t spread to other organs, however, once it is diagnosed, Dr Cisse explained that it is nearly impossible to target.
Unlike other types of brain cancer which are more specifically located, glioblastoma can occur in any part of the brain.
‘By the time a glioblastoma is diagnosed, microfibers can spread to the rest of the brain which an MRI would not spot,’ Dr Cisse told Daily Mail Online. ‘So even if the main tumor is removed and the patient receives radiation and chemotherapy, it will come back.’
Because the tumor likely already spread deep into the brain by the time it is diagnosed, the cancerous tissue is incredibly difficult to remove.
Dr Cisse said a surgeon will only even remove the tumor, or part of the tumor, if it won’t do any damage to the surrounding brain tissue.
Glioblastoma is the most aggressive tumor that can form in the brain. Patients have a 10 percent chance of surviving five years
It is most commonly found in men aged 50 to 60, and there is no link between developing glioblastoma and having a previous history with other types of cancer.
We cannot know if Senator McCain’s five-and-a-half years of captivity in Vietnam during the war could have increased his risk of developing the tumor, Dr Cisse said.
Intense exposure to radiation is the only known risk factor for brain cancer.
‘We wondered whether nature could provide a weapon to target the cells most likely responsible for this return.’
Zika virus appears to disrupt fetal brain development by preferentially targeting neural stem and progenitor cells, however the virus’ effects on adult brains are generally much less severe.
Co-director of the study Professor Michael Diamond said: ‘We hypothesised that the preference of Zika virus for neural precursor cells could be leveraged against glioblastoma stem cells.’
The researchers found the virus infected and killed patient-derived glioblastoma stem cells compared with other glioblastoma cell types or normal neural cells.
When mice with aggressive glioma were injected with a mouse-adapted strain of Zika virus, the virus slowed tumor growth and significantly extended the animals’ lifespan.
The team also tested a mutated strain of Zika who just so more sensitive to the body’s immune response, which was more effective when combined with a chemotherapy drug, temozolomide, that usually has little effect on these cells.
Co-director Professor Jeremy Rich, from the University of California, San Diego and the Cleveland Clinic Lerner Research Institute, added: ‘This effort represents the creative synthesis of three research groups with complementary expertise to attack a deadly cancer by harnessing the cause of another disease.
‘Adults with Zika may suffer less damage from their infection, suggesting that this approach could be used with acceptable toxicity.’
Prof Diamond said: ‘We showed that Zika virus can kill the kind of glioblastoma cells that tend to be resistant to current treatments and lead to death.
‘Our study is a first step towards the development of safe and effective strains of Zika virus that could become important tools in neuro-oncology and the treatment of glioblastoma.
‘However, public health concerns will need to be addressed through pre-clinical testing and evaluations of the strains’ ability to disseminate or revert to more virulent forms.’
The researchers say if the viruses was used on humans it would be injected directly into the brain during surgery to remove the tumor. The study was published in The Journal of Experimental Medicine.