Scientists at the Stanford University School of Medicine have shown for the first time that severe brain cancers integrate into the brain’s wiring.

The tumors, called high-grade gliomas, form synapses that hijack electrical signals from healthy nerve cells to drive their own growth. Experiments demonstrated that interrupting these signals with an existing anti-epilepsy drug greatly reduced the cancers’ growth in human tumors in mice, providing the first evidence for a possible new way to treat gliomas.

A paper describing the findings was published online Sept. 18 in Nature.

“One of the most lethal aspects of high-grade gliomas is that the cancer cells diffusely invade normal brain tissue so that the tumor and the healthy brain tissue are knitted together,” said senior author Michelle Monje, MD, PhD, associate professor of neurology and neurological sciences. The discovery helps explain why gliomas are so intractable, she added. “This is such an insidious group of tumors. They’re actually integrating into the brain.”

The study’s lead author is postdoctoral scholar Humsa Venkatesh, PhD.

Discovering that tumors wire themselves into the brain was “unsettling,” Monje said. Still, she said she is optimistic about what the knowledge means for glioma patients. Several drugs already exist for treating electrical-signaling disorders such as epilepsy, and these may prove useful for gliomas, she said. “There is real hopefulness to this discovery,” she said. “We’ve been missing this entire aspect of the disease. Now we have a whole new avenue to explore, one that could complement existing therapeutic approaches.”

How the tumors grow

High-grade gliomas form synapses with healthy neurons that transmit electrical signals to the cancerous tissue, the study found. The tumors also contain cell-to-cell electrical connections known as gap junctions. Together, the two types of connections allow electrical signals from healthy nerve cells to be conducted into and amplified within the tumors.