Duncan Glew is 15 years old. When he was 12 and living in his hometown of Seattle he was diagnosed with leukemia.

Glew and his family now live in Philadelphia. But back in Seattle, the Glews would take part in a charity event called the Big Climb — kind of like a run or walk to raise money and awareness for a cure, but up the stairs of a skyscraper.

Philadelphia didn’t have a Big Climb until the Glews brought it here. Actually, Duncan’s mother Gwen Glew said it was all the 15-year-old’s doing — he wanted to host a Big Climb in the Comcast Center, and after sending an email to an executive at the company, he managed to convince the company to host the event.

Big Climb Philly will take place April 23, when participants will climb 1,092 steps to the 43rd floor. Glew said the climb takes about 20 minutes to complete. So far, just under 400 people have signed up.

“Part of the reason we wanted to do the climb this part of the year is [Duncan] will be finishing his chemo March 20,” said Glew, adding that her son’s health has been a bit difficult at times due to switching between medications. Not only has the chemo been tough on his body, but he’s suffered side effects from some of the medications he’s been on.

“His bones have necrosis of the knees,” she said. “He is not actually able to climb because his bones are so fragile they could literally fracture and collapse in on themselves.”

But there’s been improvement the past year. Glew said hopefully next year, her son will be able to participate.