A friendship that ended way too soon sparked 14-year-old Alexa Sankary's desire to help cancer patients.
When she was 8, Alexa lost her best friend, 7-year-old Michael Mancuso, to neuroblastoma, a rare cancer of the sympathetic nervous system.
Shortly afterward, with the help of friends and family, the Fort Worth girl started a 5K to raise money for neuroblastoma research.
Her effort is paying big dividends.
On Saturday in Fort Worth, more than 2,000 people attended the sixth annual neuroblastoma event, The Blast 5K Run & Walk.
It raised more than $50,000.
"It started as a promise to my friend," said Alexa. "But it's really grown into something bigger."
Donations this year surpassed the group's goal of $200,000, with more than $170,000 raised before Saturday.
Since its first event in 2008, the group has raised more than $500,000.
Proceeds go to Cook Children's Health Care System to fund neuroblastoma research.
Michael's grandmother Cathy Mancuso said Alexa and Michael, who were neighbors, became friends at an early age.
"Alexa was in kindergarten the year Michael was diagnosed," Mancuso said. "She was always there for him. ... She is just an amazing little girl."
Alexa was by Michael's side every day the week before he died, telling him how they would someday drive cars and go to college together, Mancuso said.
"She would say the things he wanted to hear," Mancuso said. "He loved her so much."
The day Michael died, he prayed for God to take care of his sisters, his brother and all cancer kids, Mancuso said.
Knowing that one of her grandson's last wishes was to help other cancer kids inspires Mancuso to continue her efforts to raise money for a cure, she said.
"When Michael was diagnosed in 2004, it was the first time I had even heard if it," she said. "I had to look it up."
In 2012, with money raised in part by The Blast, Cook Children's built a specialized MIBG therapy unit -- a promising treatment in which doctors use liquid radiation to target neuroblastoma cells in relapsed patients.
"We are thrilled to offer this new era of treatment to families in this region and are thankful to have the support of The Blast which helped bring this center to Cook Children's," said Grant Harris, vice president of Cook Children's Health Foundation.
Mike Sankary, Alexa's father and a race organizer, said the courage of young cancer victims is inspirational.
"We had no idea when this adventure started six years ago that our lives would be touched time and time again by this rare and aggressive form of pediatric cancer through neighbors, co-workers, classmates, and friends," he said.