Sisters Search for Link After Rare Cancer Hits Family Twice

A new study says a genetic mutation could affect rare cancer.

December 8, 2014, 5:21 AM

— -- When Carrie Davis's father was diagnosed with a rare brain cancer, her first thought was that it was impossible for lightning to strike twice.

Her grandmother had died of the same cancer 30 years before, but her father's doctor assured her it wasn't genetic.

"He said unequivocally there is not [a link,]," Davis said. She recalled the doctor telling them her family just had "bad luck."

Her father and grandmother died of a rare but devastating brain cancer called glioblastoma multiforme. Those diagnosed with glioblastoma multiforme, the most deadly form of glioma cancers, live on average for about 14 to 15 months after diagnosis -- a timeline that has barely expanded despite decades of medical research.

But glioma cancers, including glioblastoma multiforme, were not thought to be hereditary.

PHOTO: Carrie Davis' dad John Davis was 70 when he was diagnosed with a rare form of brain cancer.
Carrie Davis' dad Jon Davis was 70 when he was diagnosed with a rare form of brain cancer.
Courtesy Carrie Davis

Davis was not convinced. So she and her sister started to look for researchers studying glioma cancers to see if anyone could prove there was a link.

"We obviously had a personal stake in this, we had my dad's DNA," Davis said. "We both had small children. We refuse to accept the premise that lightening would strike twice in our family."

Davis and her sister, Hadley Rierson, found Dr. Melissa Bondy, the associate director of cancer prevention and population services at the Baylor College of Medicine. Bondy has studied gliomas for 30 years and was in the middle of a project looking for signs that they could be more prevalent among certain families.

Davis sent Bondy an email out of the blue, praying it wouldn't go unanswered.

"I said 'This is a cold call. I've had two members of my family, my dad and grandmother have glioblastoma multiforme," remembered Davis. "She wrote me right back, and my sister and I got on the phone with her."

For the first time, Davis and her sister had hope that their hunch was correct.

"[Bondy] helps us understand the very complicated genetic parts of this," Davis said. "She has a brilliant way of making very complicated things plain."

Bondy had been working on a study as the principal investigator of the Gliogene Consortium, a group of brain tumor researchers from around the world primarily funded by the National Cancer Institute. The study focused on finding families with multiple members fighting the disease to see if there was a common genetic component.

This week, the results of Bondy's study were published in the Journal of National Cancer Institute. The study's findings point to a specific genetic mutation that could be related to an increased risk of developing certain glioma cancers.

"I have been researching familial glioma for nearly 30 years, and this study is really the first time we have had a hit when it comes to identifying a gene that is potentially associated with predisposition to the disease," Bondy said.

Bondy and her colleagues were able to do advanced genetic testing on 90 individuals with glioma from 55 families participating in the project. A mutation on a gene dubbed POT1 was found in two of the families.

One family had six members with the mutation, three of whom developed glioma cancer. In another family, two members developed glioma cancer out of six with the mutation. The cancers were associated with a kind of cancer called oligodendroglia, a less deadly form of glioma than glioblastoma multiforme.

Bondy says the findings are preliminary and more work needs to be done to understand them.

Dr. Harley Kornblum, a pediatric neurologist and brain cancer researcher at UCLA, agreed more research is needed, but said the study is certainly interesting.

Kornblum said if further testing shows more evidence that this gene is involved in cancers, researchers will understand more about its importance and what it does in the body.

In 2010 about 22,000 people were diagnosed with glioblastoma multiforme and 13,400 people died from it, according to the National Institutes of Health.

"Just because it's a rare disease doesn't mean you don't study it," Bondy said.

PHOTO: Carrie Davis is shown here in a childhood photo with her father John Davis.
Carrie Davis is shown here in a childhood photo with her father John Davis.
Courtesy Carrie Davis

Despite the trauma of watching their father die, Davis and Rierson said they felt validated to know that their hunch was right and were inspired to do whatever they could to help the researchers.

Eventually they brought up another question that had been nagging them: could their Jewish heritage make them more likely to develop the disease?

"We were going with our gut... We wanted to know if anyone had looked at ethnicity and glioma," Davis said, adding that Bondy "didn't laugh" at the idea. Instead, Davis remembers Bondy saying "I think it's something to look into."

The sisters are now helping to fund a study at Baylor to see if people of Ashkenazi Jewish descent are more predisposed to develop glioma cancer. Davis raised part of the money through Disney's matching gift program, where any employee can donate to a designated cause and the company will match up to $15,000. Davis is the vice president of communications at the Interactive Media Group at Disney, which is the parent company of ABC News. Disney donated $15,000 to the study through this program.

Davis' father passed away this summer, about a year after his diagnosis, after the new study got underway.

"Even now that my dad's passed, I think it's been helpful through the grieving process to be able to focus on this work," she said.

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