Positive thinking is always a good thing. It is a key tactic taught to Navy SEALs as they battle impossible odds and grueling physical challenges. It's been known to help golfers and other professional athletes stay in the zone and it has been shown to make you seem more attractive to the opposite sex.
Now research has shown that the simple act of thinking can accelerate the growth of many brain tumors.
Those are the findings of a paper in Cell, published on Thursday, that show how activity in the cerebral cortex of the brain affects high-grade gliomas, which account for about 80 percent of all malignant brain tumors in people.
"This tumor is utilizing the core function of the brain, thinking, to promote its own growth," says Michelle Monje, a researcher and neurologist at Stanford who led the research team.
Based on the findings the theory would be that doctors could slow the growth of these tumors by using sedatives to reduce mental activity. But that isn't practical in real life because it wouldn't eliminate the tumor and "we don't want to stop people with brain tumors from thinking or learning or being active."
But the discovery alludes to other ways to slow down some of the trickiest brain tumors, says Tracy Batchelor, director of the neuro-oncology program at Massachusetts General Hospital.
"We really don't have any curative treatments for high-grade gliomas," Batchelor says. The discovery that tumor growth is linked to brain activity "has opened up a window into potential therapeutic interventions," he says.
The discovery came after a team of scientists implanted human glioma tumors in mouse brains. The scientists used a process called optogenetics that uses light to control brain cell function. The technique increased the activity of cells near the tumors.
The team was lookin to see if high levels of activity would make the glioma grow more quickly. "And it turns out that it did,"
She began to suspect that this rare form of cancer was somehow hijacking a process called myelination, which happens in healthy brains. the Myelination process creates a layer of insulation around nerve fibers, which makes them better able to carry signals.
Last year, Monje andher team showed that the cells responsible for myelination began to grow quickly in response to heightened brain activity. "That was an intriguing finding and it was consistent with our idea that activity in the brain, thinking, planning, using your brain, might be promoting the cancer arising within it," she says.
The mouse experiment confirmed the team's suspicion. An additional experiment showed that the cancer cells were growing in response to the chemical signals that typically cause myelination.
"This work has much broader implications for brain tumors," says Batchelor. "It's not just pediatric tumors [the initial target], it's pediatric and adult. And it's not just one particular type of glioma. This has potential implications across the entire family of gliomas in the brain."
Batchelor says the new research suggests a possible way to slow down these tumors — by disrupting the pathways linking brain activity to tumor growth.
Monje says she is glad that her work has led to a better understanding of tumors but says it's still hard to feel gratified.
"It will be gratifying when we make some difference for these kids," she says.