Wilton Rallies Around “Extraordinary” 6-Year-Old Greta DuBrock as Family Pursues Experimental Brain Cancer Vaccine

Wilton resident Emily Mueller DuBrock describes her daughter Greta as the sort of child who “isn’t afraid to put her grandmother in a time out.”

“Greta has always been extraordinary,” DuBrock said in an email exchange with GMW. “She’s the type of kid who gets an award in preschool for being wise beyond her years. She is funny — she tells it how she sees it.”

She’s also been fighting a rare brain cancer for most of her young life.

When Greta was just two years old, DuBrock took her to the pediatrician after Greta experienced headaches and vomiting. Within days, Greta had a diagnosis of ependymoma, a rare brain cancer, and underwent a nine-hour major brain surgery.

“No one is ever prepared to hear your child has cancer,” DuBrock said. “And I swear, every time the doctor says there is a recurrence, I am shocked. Greta’s cancer can grow while she is thriving. People often don’t find it until a child has impaired walking, speech or gaze.”

Despite aggressive treatment and multiple surgeries, Greta’s cancer has returned repeatedly — once in 2024 and now again this year.

While she was well enough to start kindergarten at Miller-Driscoll School this year, she underwent her fifth major surgery on Sept. 15, which successfully removed the latest tumor growth.

As of Oct. 26, Greta was still in the hospital but was expected to move to a rehabilitation facility within days, according to Melissa Leonard, a close family friend who has been helping lead the support effort with fellow Wilton resident Erin Thomas.

The Second Blow

Greta’s terrifying diagnosis came just 18 months after another devastating loss: the sudden, unexpected death of Greta’s father, DuBrock’s 44-year-old husband, Mark, in 2021.

In the midst of her family’s grief, DuBrock navigated the complexities of Greta’s recurring cancer while also caring for her three other young children, now in their teens. DuBrock didn’t leave Greta’s side during numerous extended hospital stays, while Greta’s siblings remained at home with a network of relatives, close friends and neighbors who stepped in to assist with essential daily needs and transportation.

“Spending the night, [ensuring DuBrock’s] other kids are able to be where they need to be, and are always surrounded by loving people who they know and trust is really important,” Leonard said. 

The Greta Initiative

“I’ve learned through years of Greta fighting recurrent cancer — a terrible game of whack-a-mole — that the standard treatments will not work for her,” DuBrock said. “We have to stop the tumors from coming back.” 

That realization led her to launch The Greta Initiative (TGI), a campaign to develop a personalized mRNA cancer vaccine for Greta.

“We’re raising money to design, manufacture and deliver a personalized mRNA cancer vaccine,” DuBrock explained. “It isn’t an off-the-shelf vaccine, but one made using information from Greta’s own tumor, designed specifically around her cancer. The goal is to teach Greta’s immune system to recognize those tumor-specific targets — and hopefully find and attack cancer cells carrying them. The goal is to prevent the tumor from recurring.”

DuBrock cited encouraging results from clinical trials of mRNA vaccines for late-stage melanoma and pancreatic cancer, but she recognizes “there’s a lot more learning to do here.” The bright spot she sees is the pace of that learning and innovation, including increasingly sophisticated molecular testing and AI-driven analysis.

“Science is moving incredibly quickly, including in personalized mRNA vaccines,” she said. “When Greta was first diagnosed four years ago, her tumor was tested against roughly 20 genetic markers. After a later recurrence, we were able to investigate thousands of characteristics of her tumor — that’s a staggering difference.”

Just as staggering is the cost to develop the mRNA vaccine for Greta, which is experimental and not covered by insurance. The immediate fundraising goal is $500,000 to fund its development.

Leonard said the effort behind TGI gained momentum after cuts in federal funding halted promising medical research and clinical trials. After DuBrock determined a realistic cost for developing a personalized vaccine, friends and family quickly rallied around the idea of raising the money needed to move forward.

The campaign officially launched in mid-September. By late October, fundraising had surpassed $83,000.

Leonard believes the goal of developing the vaccine for Greta is within reach.

“I feel like we’re on the precipice of getting it done,” Leonard said. “We’re going to figure it out and get it done.”

DuBrock’s ultimate mission is even more ambitious, extending beyond her daughter’s treatment. As Leonard explained, TGI’s eventual goal is to raise a total of $1 million, with the additional funding intended to help another child obtain their own personalized mRNA vaccine. 

DuBrock has connected with roughly a dozen families who have a child with ependymoma. They have shared treatment histories, testing results and other information, although their collective experience underscores how unique each case is.

TGI aims to build on that knowledge base and share what emerges from Greta’s treatment experience.

Developing a vaccine for Greta will be an arduous process involving genomic sequencing, vaccine design, regulatory approval hurdles, and coordination among doctors, laboratories, funding sources and more. The hope is that what is learned through TGI could help open doors, streamline the process and expedite vaccines for other children like Greta who have not benefited from standard care.

Grateful for Wilton

“Walking this path is surreal. I can’t believe that we’re on it but we are,” DuBrock reflected. “And all I can do is take each step forward. Greta does it every single day.”

“What helps make that possible is our friends, family members, neighbors and the kindness of strangers who care about Greta and support us in ways big and small,” she continued. “Wiltonites have been showing up for Greta and our family for years. Wilton is just that kind of place.”

She also acknowledged Wilton’s strong faith community, specifically the Wilton Congregational Church, for its strong support.

DuBrock said she’s “grateful to be fighting this fight in Wilton.” She said her sisters who live out of state refer to Wilton as Mayberry because it’s “so idyllic.”

“We’re always helped along by neighbors and friends in incredibly thoughtful ways,” she said.

She recalled her son’s football friends who arranged gift cards to the family’s favorite restaurants, and Wilton schools that sendt cards and even a special Halloween song for Greta while she’s been in the hospital.

“And so many meal trains, I can’t even count them all,” she continued. “Rides for Greta’s siblings to practice, games, events… And now, friends and Wilton kids offering to help fundraise for Greta’s vaccine. They’re out spreading the word around town and it means so much.”