October 16, 1998

David Louis, MD

Collaborative study finds first genetic clues to brain tumor treatment

A team of researchers from the MGH and the London (Ontario) Regional Cancer Centre have discovered genetic changes that indicate whether chemotherapy would be effective in treating anaplastic oligodendrogliomas, a particular type of brain tumor. The discovery, described in the Oct. 7 Journal of the National Cancer Institute, has the potential for significantly improving treatment of patients with these tumors.

Patients whose tumors have the genetic pattern identified in this study – loss of a portion of chromosome 1 – have excellent treatment results with chemotherapy, a treatment that is ineffective against most brain tumors. Patients without the identified pattern can avoid the toxic side effects of chemotherapy.

David Louis, MD, of the MGH Department of Pathology and Neurosurgery Service, the paper's senior author, says, "This is the first time that molecular genetic analysis has been applied successfully to the diagnosis of brain tumors and the first time we've been able to define which brain tumors are going to respond to chemotherapy." Molecular genetic analysis – the use of genetic information to classify tumors, as opposed to traditional methods that rely on a tumor's physical appearance – has been used for several other sorts of tumors.

Louis and his MGH team collaborated with a London group led by J. Gregory Cairncross, MD, that previously had discovered oligodendrogliomas' sensitivity to chemotherapy drugs. Louis and his group had identified a number of genetic variants in the malignant brain tumors called gliomas; combining their expertise, the researchers found that the chromosome 1 loss was powerfully and significantly associated with response to chemotherapy.

"This means that patients whose tumors have this defect have an excellent chance of surviving at least five years after diagnosis because virtually 100 percent of these tumors respond to chemotherapy," says Louis. Other MGHers on Louis's research team are Keisuke Ueki, MD, David Lisle, Dianne Finkelstein, PhD, Jonathan Silver, Paul Stark, MS, and Yasushi Ino, MD.