As the wind whistled through the trees and the mist settled, parents, children and students alike raced around the foggy Chestnut Hill Reservoir in the “Costumes for Cancer 5k Fun Run and 2.5k Walk” Sunday morning. They had the option to dress up in Halloween costumes, and all proceeds from the run benefited The John Estrella Foundation for Cancer Research.

The John Estrella Foundation for Cancer Research was founded in memory of John Estrella, who died from kidney cancer in 2004. The organization holds annual philanthropy events, such as the John “Ace” Estrella Golf Tournament, and often donates large research grants to Boston hospitals to expand their kidney tumor registry.  

“He was very positive,” said the organizer of the event, Elicia Estrella, the daughter of John Estrella. “He joined clinical trials and did so much to help other people with kidney cancer, knowing it wasn’t really going to help him.”

The 5k run has been held annually since 2016 to honor Estrella’s legacy, but this is the first year Boston University’s Graduate Medical Sciences Student Organization had a team participating together at the run/walk to raise money.

“So, we decided to start this foundation, mostly family and friend volunteers … and 99 percent of the funds we raise go to research, awareness and support of families with kidney cancer,” Estella said.

Local businesses also contributed to the cause by donating to The John Estrella Foundation for Cancer Research and providing a post-race “trick or treat” experience. After the run, participants were able to grab a treasure map that led them to different businesses around the area that then provided free food and beverages like pizza, bubble tea and candy.

Ari Kendall, owner of Chik Chak Food Truck, participated in the “trick or treat” experience by preparing dishes of falafel, pita and hummus for hungry runners.

“It’s good to get people out and in the public’s view,” Kendall said. “With a run outside and attractions such as myself, it’s a good way to bring awareness to the cause.”

Parents and children alike stood about laughing after the race, enjoying snacks and commenting on the original, unique costumes some had donned for the run.

The costumes ranged from a runner dressed as a shower to Courtney DeGeorge, one of the main coordinators of the run, wearing a taco-shaped hat.

“It’s a fun, family-friendly race,” Estella said. “We have winners for the actual race and then winners for the best costumes. I think it promotes a good sense of community and allows people to come out who maybe don’t run all the time and bring their children in fun costumes.”

Anh Kuettner, 40, who ran in the 5k, seconded Estrella’s sentiments.

“It’s a fun way to spend time with some great people and do it for a great cause,” the Marlborough resident said. “Every year, I always love seeing people run with all the different costumes on. Everybody’s always having fun.”

There was a lower turnout this year compared to previous years due to Sunday’s rain, according to Estrella, but still a significant crowd showed up. Kendall said it was a way to join together in a festive, light-hearted way.

“My grandmother just beat breast cancer,” Kendall said as he stirred the falafel in the deep fryer. “And yesterday was her birthday, so this just seemed like a good thing to do.”

Despite the mist in the air and the chill in the wind, children ran about while adults chatted with one another.

“If I could have people take one thing away from this event,” Kendall said, “it’d just be to get out, do something you care about and eat falafel.”