A Big Push to Beat a Nerve Tumor
Date: November 1, 2011
Patients with schwannomatosis face a double-whammy. Not only does the disorder produce debilitating pain caused by hundreds of schwann-cell tumors growing throughout the myelin sheaths around the nerves, but it is so rare that few neurologists or neurosurgeons have seen it. At the Johns Hopkins Comprehensive Neurofibromatosis Center, both types of specialists have come together to care for patients and find potential breakthrough treatments for these tumors and other forms of the peripheral nerve tumors known as neurofibromas.
Neuro-oncologist Jaishri Blakeley, director of the center, has been searching for a drug that can block the chemical messages on which the tumor cells are relying for growth. By examining the tumors removed from patients with neurofibromatosis type 2, she has already proved that experimental drugs are making their way in good concentrations into the tumors rather than being blocked as some drugs are by the “blood-nerve barrier”—a chemical defense analogous to the blood-brain barrier that makes it so difficult to get drugs into the brain.
The ability to assess a drug’s access to and activity in tumors following surgery can help to more quickly screen drugs to find the ones most likely to justify the substantial investment of a larger clinical trial. “It would be fantastic to hit on a cure right away,” says Blakeley.
“It’s a giant step forward to eliminate those drugs that don’t work so we can move on to others.”
Another big breakthrough would be a long-sought-after means to quickly catch neurofibromas that are becoming malignant. To that end, neurosurgeon Allan Belzberg has been collaborating to apply an advanced MRI technique called neurography to spot these nerve malignancies. He’s also working in the laboratory to hunt down a biomarker for these tumors that would allow detection with a simple blood test.
Meanwhile, when a peripheral nerve tumor becomes malignant or impairing, Belzberg not only removes it, he surgically repairs damaged nerves by splicing in nerves from an arm or leg to restore some of the otherwise lost function. That’s a dual treatment not often available outside the center. “Losing the ability to flex an elbow can make an arm useless,” he says. “By repairing the damaged nerve or rewiring the system we can help recover much of that muscle control.”
- Challenge: Catch and treat peripheral nerve tumors, especially malignant or painful ones
- Approach: Splice in nerves to repair damage, find diagnostic tests and develop a drug cure
- Progress: Muscle control can be restored, imaging is catching malignancies, drug screening is under way