New Hope To Fight Brain Cancer In Children

By Margarita Nahapetyan

The family of eight similar genes mutating in young patients with the most common form of childhood brain cancer - medulloblastoma - have been discovered by Canadian scientists, who now have the opportunity to create less toxic treatments for the brain tumors.

Dr. Michael Taylor, a pediatric neurosurgeon at the Hospital for Sick Children, and the lead scientist of a new study, said that they are just one step away now in their search for a better treatment of a deadly disease. "We think what this family of eight genes does is it is responsible for telling the cells when to grow up. When these genes are mutated the particular cell in which the mutation has arose does not stop growing, it keeps going," he said.

Medulloblastoma starts typically in the lower part of the brain in the cerebellum, and can spread to the spinal cord or other parts of the body. Brain tumors, including medulloblastoma, are the leading cause of childhood cancer mortality. It is primarily a disease of children at a very young age, and is particularly deadly among babies under 18 months of age. Although about 60 per cent of all kids diagnosed with medulloblastoma now survive at least five years, in most cases they are left with severe physical and neurological disabilities from both the disease and the treatment.

In their study, the largest of its kind, Dr. Taylor and his colleagues examined more than 200 medulloblastomas that have been surgically removed from children from all across the world, including countries such as Canada, the United States, UK, Poland and Saudi Arabia. The data was analyzed and interpreted for the period of three and a half years. As a result, eight mutated genes have been discovered in a group that is responsible for switching off growth-promoting genes in the brain.

In other words, researchers realized that when the eight genes work in a proper way, they send signals to the neurons in the rear part of child's brain when it is time to stop growing. But when any one of the eight genes is out of order, the region remains in an immature state and never grows up. Cells start multiplying without control, indefinitely, and trigger tumors that kill 40 per cent of all affected young patients within five years.

Paul Northcott, a PhD student in Dr. Taylor's lab, who participated in the research, said that the new study revealed much more about the genetic basis of the condition, than did all the previous investigations on this matter. According to him, the progress in the human genome project and modern technology to detect mutations, have achieved such levels today, that one person is being able to do what required thousands of people just a decade ago.

The scientists say that with appropriate funding they would be able to continue their investigation and better understand the process of gene mutations in children's brains. After that, they plan to figure out how to address in the best ways those mutations in order to treat children more efficiently and decrease the complications after surgery, radiation or chemotherapy. Dr. Taylor says that some drugs are already being created, to fight the type of proteins that are missing in the kids' brains with the gene mutations. "Our hope is that some of these drugs may be adapted and used effectively to treat medulloblastomas," he says.

The research is published in the online edition of the journal Nature Genetics.