Old Lyme - Caroline O'Brien was a blond-haired little girl who enjoyed playing soccer, eating cookie dough ice cream and laughing with her siblings.

When she was diagnosed in 2009 with diffuse intrinsic pontine glioma - an inoperable brain tumor - she, her parents, her brother and two sisters set out to make sure that from that point on, her life would be full of fun.

Even though she had her own battle to fight, Caroline wanted to make other children smile. So, with a smile that would become the official logo, she started Caroline's Miracle Foundation in order to help other families affected by the devastating diagnosis.

In July 2010, at 11 years old, Caroline succumbed to the disease.

The foundation has since pushed forward and to date has created "mini miracles" for 17 children and teens throughout the Northeast. The foundation's biggest fundraiser, the 5K and Fun Run/Walk now in its third year, will take place Saturday in conjunction with the Old Lyme Midsummer Festival - Caroline's favorite weekend of the summer.

She was diagnosed with DIPG the morning of the start of the Midsummer Festival in 2009. The O'Briens took Caroline to the doctor when she complained of headaches, vision problems and had trouble swallowing her food, all symptoms of DIPG.

Nearly 300 runners or walkers have signed up for the race, which her mother, Jennifer O'Brien, said will make Saturday's race the foundation's biggest yet.

"This community has been so great to us. This is really our only official fundraiser for the foundation," O'Brien said Thursday as the family prepared for the event. "We like to keep Caroline present in the community."

DIPG comprises 10 to 15 percent of all brain tumors in children, with about 100 to 150 new diagnoses per year in the United States and about 300 per year in all of North America and Europe, according to the DIPG Registry. It is the most common form of brain stem glioma in children.

O'Brien described the tumor and its effect on children as "unthinkable," and a "horrible, horrible thing."

"There is no cure. You can't operate. The tumor is like sand. It's everywhere. It's intertwined with the nerves," Caroline's father, Michael O'Brien, said. "They're currently doing research for a cure, but most medicines and radiation treatments just prolong."

The O'Briens said it was impossibly difficult to tell their child, who was 10 when she was diagnosed, that most children who are diagnosed with DIPG do not live beyond nine to 18 months after diagnosis.

"When Caroline was sick, she got to do a lot of things - Disney World, meeting Taylor Swift, Selena Gomez. ... Katie Stevens from American Idol sang for us in our living room," Michael O'Brien said. "Caroline said we needed to help kids with brain tumors do really fun things."

Paying it forward

One of the first to receive a mini-miracle from Caroline's foundation was Meg Wasley.

The North Carolina resident, who was 8 when she was diagnosed with DIPG, was being treated in Rhode Island and was staying at the Ronald McDonald House there.

Caroline's foundation surprised Meg with a shopping spree at Toys "R" Us.

"Jen (Caroline's mother) was just throwing stuff into the basket, telling Meg, 'You need this, you need that, here's an Xbox,'" Meg's mother Terri Wasley said Thursday. "She had everything. I mean, carts filled to the top. It was absolutely amazing. Meg was smiling and laughing."

Three weeks after the shopping spree, Meg died of an infection common in children undergoing radiation.

"The shopping spree was the last time we really saw her truly happy," Wasley said. "When we drove away from Rhode Island, we knew we were going to be in the same position as Jen. We wanted to do the same thing she did because it created a memory we would never forget. We're trying to pay it forward."

The Wasleys started Meg's Smile Foundation, a nonprofit foundation based in North Carolina that also benefits seriously ill children.

Jennifer O'Brien said the tenacity of her daughter to fight to live helps the family cope with their loss.

"We're just really proud of her, that's the bottom line," she said. "I hate when people say she lost her battle, because anyone who has the courage to fight could never lose. I don't know why people say that ... because I really feel like she won."

j.hanckel@theday.com

IF YOU GO

Who: Caroline's Miracle Foundation

What: Third annual 5K and Fun Run/Walk

When: Registration will run from 6:45 a.m. to 8:15 a.m. Saturday. Race starts at 8:15 a.m. for the fun run, 8:30 a.m. for the walk and 8:45 a.m. for the run

Where: Register at Lymes' Youth Service Bureau, 59 Lyme St., Old Lyme

What else: The fee is $25 for the 5K run, $15 for the 5K walk and $10 for the 1-mile Fun Run

More information: www.carolinesmiraclefoundation.org