Canadian researchers say they have made a key discovery that might explain how a rare and deadly childhood brain tumour develops, and they believe that existing drugs used to treat adults may slow or stop the tumour's growth. But they can't test their theory because they haven't been able to find funding for a clinical trial.
"As a clinician, it's very frustrating," said Dr. Annie Huang, an oncologist and brain tumour specialist at Toronto's Hospital for Sick Children, who helped lead the new research.
The brain tumour, known as ETMR/ETANTR, typically strikes children under age four and is extremely aggressive. Doctors try various drugs and radiation to treat the disease, but those treatments are usually ineffective. "Right now, literally it's almost a death sentence," Huang said. "More than 90 per cent of kids [diagnosed with the disease] will die."
After years of studying this vexing cancer, Huang and colleagues from McGill University Health Centre discovered that a certain gene is activated or "turned on" in children with this brain tumour, and it causes production of a specific enzyme. Their findings were published online this week in the journal Nature Genetics.
They believe the enzyme is tightly linked to the development of ETMR/ETANTR and fuels tumour growth. Huang said that means the key to helping children with this disease could be targeting the enzyme.
"If you can inhibit that enzyme, you can revert it back to normal," Huang said.
Their discovery is an important example of how epigenetics and personalized medicine are increasingly being used to find new ways to treat disease. Epigenetics refers to changes that can turn genes on or off. These changes can, among other things, spur tumour growth. The field of personalized medicine focuses on using an individual's specific genetic code to come up with a tailored medication or treatment that will work for them.
For patients and their families this is potentially significant because existing drugs can be used to target the enzyme, known as DNMT3B. The drugs are known as DNA methylation inhibitors, and researchers have already seen promising results from experiments using cancer cells collected from young patients.
The current treatment regimen for ETMR/ETANTR doesn't work on the majority of patients. The small number of patients that can be helped also face major side-effects that include intellectual and developmental impairment caused by the radiation and drugs.
In order to move forward, Huang and her colleagues want to test DNA methylation inhibitors on children with this rare brain tumour. Funding is difficult to secure because the tumours are so rare, Huang said. In these cases, international researchers typically team up to increase their chances of securing a clinical trial grant, but right now, it's unclear when the funding may come.
Carly Weeks