A poorly understood type of childhood brain cancer has a unique molecule signature that may point to which therapies could best fight it. Armed with targeted molecular treatments, doctors may be able to fight the disease without risking the side effects of prolonged and powerful radiation and chemotherapy at an early age.
The latest research is a collaborative effort looking at a type of childhood tumour known as medulloblastoma, the most common childhood tumour of the CNS. The cancer usually strikes between the ages of 5 and 10. Medulloblastomas are highly malignant, and can spread to the spine and other parts of the body. But over the past few decades, refined treatments have increased survival rates until approximately 80 percent of children survive for five to 10 years after diagnosis.
But the therapies aren't perfect. Radiation and chemotherapy for up to a year at such a young age can lead to hearing loss, cataracts and severe learning disabilities that can leave children unable to live independently in later life.
Led by Dr. Scott Pomeroy, an associate professor of neurology at Children's Hospital in Boston, the researchers found that increased activity of Sonic Hedgehog (SHH), a signaling molecule crucial to brain development, is linked to one type of medulloblastoma. "As compared to chemotherapy, which is non-specific and damages all cells ... these very focused treatments will only work on those tumors that have that particular molecular pathway active," says Pomeroy.
Recently developed compounds that can block the uncontrolled SHH signaling found in the tumors could potentially be used as a therapy in children with medulloblastoma. Researchers also found that the clinical outcome of an individual child's struggle with medulloblastoma could be accurately predicted by examining the patterns of gene expression in the cancer at the time of diagnosis.