New Research Shows Promise for Pediatric Brain Tumor Treatment

Every year, about 4,700 children in the United States are diagnosed with brain cancer –­ making it the most common solid tumor in children.

Alisha Savage, a 4-year-old pediatric brain tumor patient, has traveled with her family from Ireland to be treated at Dana-Farber/Boston Children's.
Alisha Savage, a 4-year-old pediatric brain tumor patient, has traveled with her family from Ireland to be treated at Dana-Farber/Boston Children’s.

It is also one of the most difficult cancers to treat. Brain tumors are the leading cause of cancer-related deaths in children under age 10 and the second leading cause of cancer deaths in people under 20.

Although survival rates for children with some types of brain tumors have risen over the past 30 years, current research aims to increase those rates dramatically in the years ahead. Scientists are focusing on the basic genetic and genomic errors that spawn tumors, and at the elements of the tumor “microenvironment” – the web of tissues and substances that surround tumors – to better understand the origins of brain cancers and how they may be combated in the future.

Some recent advances include:

  • To improve the ability of some chemotherapy drugs to reach brain tumors, investigators have coated some of these drugs with tiny layers of fat, which may help them cross the blood-brain barrier, the mesh of capillaries that protects the brain from foreign substances. Another approach under study is to attach chemotherapy agents to molecules that normally cross the blood-brain barrier.
  • Researchers have recently generated a first-of-its kind mouse model for pediatric low-grade gliomas, cancers that arise in cells that support and surround nerve cells in the brain. The new model, in which tumor cells carry the same genetic alteration found in human tumors, will enable scientists to better predict how effective new drugs will be in patients.
  • Researchers at Dana-Farber/Boston Children’s and McGill University have found several molecular alterations that drive a rare, fatal pediatric brain tumor known as high-grade astrocytoma. Such tumors are extremely difficult to treat with radiation and surgery. At least two of the newly found gene alterations, or mutations, found in one form of high-grade astrocytoma might be susceptible to blocking by existing drugs.
  • Another group of scientists at Dana-Farber/Boston Children’s identified a mutated gene that causes tenacious brain tumors known as papillary craniopharyngiomas. Though benign, such tumors can have severe lifelong effects. In children, the tumors often carry a mutation in the gene CTNNB1, the researchers found, which spurs an onslaught of growth in tumor cells. Although no CTNNB1-blocking drugs have yet reached the clinic, several groups are working on developing them. The discovered mutated gene – BRAF – is responsible for craniopharyngiomas in adults. The finding was especially encouraging because drugs exist that inhibit this gene’s effects.
  • Scientists have long known that cancer cells with a high oxygen content are particularly vulnerable to radiation therapy. Investigators are exploring whether drugs that increase the oxygen supply in tumors can enhance the effectiveness of radiation therapy in pediatric brain cancer patients.
  • Dana-Farber/Boston Children’s researchers have found that pediatric low-grade gliomas often harbor an unusual genetic mutation that may help to classify, diagnose, and guide the treatment of the tumors. An analysis of several dozen tumor specimens revealed that a gene called MYBL1 was rearranged or missing a part of its genetic message in nearly 30 percent of them.