The event aims to fundraise for the Dream Chaser Foundation which Keri and Ryan set up after Chace died. The foundation promotes bone marrow and blood donation and provides support for children and their families facing cancer.
"Many children need bone marrow transplants but if you are Maori, Pacific Island or any other ethnic minority group, your chances of finding a match drop substantially," Keri said.
A match was unable to be found for Chace. He ended up having a stem cell transplant although it wasn't considered the ideal treatment option.
Ryan and Keri, who lived in Hamilton for eight years and now live in Whakatane, considered what services could have helped their family during their journey and decided practical support was what they'd have most benefited from.
"So we organise birthday presents, Christmas hampers, random visits to Starship Children's Hospital, just making children smile," Keri said.
"The sad reality is that not everyone has a good outcome so we offer bereavement grants and support too."
But running the foundation isn't easy.
"It's the most difficult job," Keri said. "It requires 24/7 energy and input. As much love and energy that went into our son goes into the charity. We want this to be a massive success, something that is everlasting."
The Topperwiens' dream for the foundation is that it will be one of New Zealand's leading childhood cancer charities and that it will become synonymous with bone marrow and blood donation.
The Hamilton fun run is the third in a series this year. Others have been held in Whakatane and at Mount Maunganui. Participants are encouraged to dress up in "fun and silly" yellow-themed costumes, a nod to Chace's favourite colour.
The Chace 'em Fun Run at Hamilton Lake, Sunday, November 3 at 10am. Register at www.dreamchaser.co.nz or sign up on the day.
Online registrations completed by 8pm October 31 qualify for $5 off entry, a chance to win back your registration fee and special spot prizes.
Entry: Children one lap $5; adults one lap $20, two laps $25, three laps $30. Barbecue, cake stall, face painting, drinks and entertainment.