Lucas "Bear" Cervone died May 1, just shy of his 6th birthday. His family had held a party for him just before his death because they worried he might not make it to the big day.
On Sunday, the annual "Move for the Kids" event sponsored by Lurie Children's Hospital will pay tribute to him.
Cervone, who battled cancer for most his life, was diagnosed with leukemia at age 2.
He was flooded with birthday cards last month after news spread that cards and letters would help him during a difficult time. The Chicago UPS Store where the cards were delivered was running out of space because so many letters were sent.