Combination Therapy for Brain Tumors Holds Promise for Longer Survival After Surgery Despite advances in neuroimaging and surgery, no major developments in the treatment of malignant brain tumors have been introduced in the past two decades. Right now, surgeons rely on radiation therapy after removal of the tumor to mop up microscopic cancerous cells that could lead to regrowth. Brain tumors, however, are extremely resistant to radiation treatment. Researchers at the University of Pennsylvania Medical Center have now found a way to make brain cancer cells more receptive to radiation treatment --by 60-fold in some cases.

"The goal of our research is to extend the survival of terminally ill patients and give them a better quality of life during that time," says Donald M. O'Rourke, MD, assistant professor of neurosurgery. "Following a diagnosis of brain cancer, median survival of patients is only 12 months with treatment." More than 17,000 new cases of brain cancer are reported each year, according to O'Rourke, and this diagnosis is nearly always fatal.

In a biochemical one-two punch to brain cancer cells, O'Rourke and colleagues inactivated a common cell-surface receptor called the Epidermal Growth Factor Receptor (or erbB for short) to arrest cell growth in human cell lines, which further sensitized the cells to radiation. This approach works in a similar way to Herceptin, the new breast-cancer-fighting drug awaiting FDA approval. Herceptin, a monoclonal antibody therapy, is based on the basic research performed by the laboratory of Mark I. Greene, MD, PhD, at Penn. Both strategies target mutated or overexpressed erbB receptor proteins that allow cancer cells to grow unchecked.

"Depending on which type of cell we used, we achieved between 20 and 60 percent cell death in cancer cells where the erbB receptor was first deactivated, versus zero to 5 percent in radiation-alone controls," reports O'Rourke. These findings were pu
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Contact: Karen Young Kreeger
kreeger@mail.med.upenn.edu
(215) 614-0290
University of Pennsylvania School of Medicine
16-Sep-1998