In deadly children's brainstem cancer, a breakthrough

Mar 1 2011 - 3:01pm

SAN FRANCISCO -- Stanford University scientists have found one of the first potential targets for treating a type of childhood brain cancer that is almost always fatal. It has been nearly impossible to study because of its location in the brain stem.

The research breakthrough came after scientists used donated tumors to re-create the cancer, called diffuse pontine glioma, in mice. That animal model will allow doctors to study how the living cancer cells behave and, eventually, to test drug therapies. The research was published online Monday in the Proceedings of the National Academy of Sciences.

"Brain tumors are pretty tough monsters to fight, especially these high-grade gliomas," said Dr. Michelle Monje, a Stanford neurologist and the study's lead author. "We still don't have a lot to offer by way of treatment. ... But we're making some progress now, and I feel very hopeful, especially with these new invaluable resources."

Monje described the disease as a particularly "horrific" cancer. A brainstem glioma often shuts down the central nervous system in months, leaving children fully cognizant but unable to talk or walk or swallow.

The aggressive cancer hits about 300 children, most between ages 5 and 9, in the United States every year. Only 1 in 100 survives more than five years.

While radiation therapy can extend a child's life by a few months to a year, there are no effective chemotherapy drugs. The cells are remarkably resilient, making them impenetrable to traditional chemotherapy, doctors said.

It's impossible to remove tumors from the brain stem because they entwine with healthy cells in the part of the body that essentially controls the central nervous system. Surgery is considered too risky.

Stanford researchers developed the first model using a tumor donated by the parents of Dylan Jewett, a 5-year-old boy who died in January 2009 two months after his diagnosis. Dylan's mother, Danah Jewett of Fairfield, Calif., said she'd asked about donating her son's organs and was told that, because of the cancer, only his corneas could be used for a transplant.

But Dylan's tumor could be used for research, and she and her husband, John, embraced the idea. Since then, five other families have donated their children's tumors to Stanford.

"I know Dylan would have wanted to help other children," said Danah Jewett. "... Even though he didn't get to live longer than the five years, he has made an amazing contribution to science."

For decades, the cancer couldn't be studied well because biopsies were considered too dangerous. But in the past year, two research teams have found ways to biopsy the tumors, allowing scientists to study living cells and identify possible molecular targets for treatment.

Stanford's mouse model will prove "exceedingly helpful" in studying the cancer and testing possible drug treatments, said Dr. Daphne Haas-Kogan, program director of radiation oncology at the University of California-San Francisco's Helen Diller Family Comprehensive Cancer Center.

"It's a very big deal," said Haas-Kogan, who serves on a committee focused on brain stem tumors. "Every six months I give a talk about potential treatments and clinical trials, and it's always a really depressing 45-minute talk. But this year was the first time I got up with enthusiasm."

The mouse model also helped Stanford researchers identify a possible stem cell and molecular pathway -- or a regularly occurring cellular activity -- that could be involved in setting the tumor cells in motion.

There are already drugs on the market -- approved for use in treating other cancers in adults -- that could halt activity on this pathway, and possibly prevent the brain tumors' growth. But the drugs have never been used on children and could have dangerous side effects, Monje said. They will need to be tested on the mice first to make sure they're effective.

Still, Danah Jewett hopes that a treatment will come from Dylan's donation. She said she constantly follows research into the disease and asks Monje when other children might see some benefits.

"There are times in my grief where I wonder what they're doing. I'm always saying, 'Have we treated any kids yet?' " Jewett said. "And she always says we're working toward it. We're close."

(Contact Erin Allday at eallday(at)sfchronicle.com.)

(Distributed by Scripps Howard News Service, www.scrippsnews.com.)

 

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