Anyone who goes the distance can tell you about the physical and mental endurance it takes to run a marathon.

There are standouts among the more than 35,000 runners registered for the 2016 Dick’s Sporting Goods Pittsburgh Marathon—world-class athletes; top U.S. long distance runners; the oldest runner, at 86; those who run for charities, or to promote wellness and teamwork.

Every runner has a story to tell about what motivates him or her to run. Some stories—such as those of Jessi Marsh here and coming soon, Pia Crosby and Jeffrey Whitmore—are deeply inspiring. They began running for mundane reasons. Over the course, each has learned tough life lessons.

Jessi Marsh

Marsh, 38, of Monroeville, wife of Kevin and mother of Cassidy, 6, started running four or five years ago. A swimmer, she became intrigued when a friend talked about how much he missed running while sidelined by a knee injury.

“I was always one of those people who would say, ‘I don’t run unless someone’s chasing me,’” she jokes. But he talked so passionately that she began training with the C25K (Couch to 5K) app, slowly working up from a one-minute run to a couple of 5K races—Color Me Rad, the Jingle Bell Run—and then a five-mile mud race to raise money for MS research. Her husband pushed her through that hilly, muddy trail, prodding, “Let’s go! You can’t stop in the middle of the woods.”

Then came her real test of resilience: a stage 3B colon cancer diagnosis in 2013. Her surgeon removed a large tumor that October. “That was pretty devastating,” Marsh recalls. She started chemotherapy on Halloween, 24 weeks of two drugs, delivered through a port implanted in her chest.

“I named mine ‘Mort the Port.’ When you have a little girl, you have to find the levity in this stuff. You can’t make cancer fun, so I’m not going to go that far, but you can make it a little less terrible.”

Marsh set a goal of running the Pittsburgh Marathon’s 5K in May 2014, training during chemo. “That’s a lot of what my story’s about—finding something hard to do, that I’m really scared of,” she says. “It’s not as scary as cancer, so I’m going to figure out how to do it.”

In remission, she tackled a triathlon last June at Moraine State Park. “A week later, I found out my cancer had come back—now stage 4—in my liver. Two spots.” Her doctors ordered two rounds of chemo, and then removed half of her liver and her gall bladder in September. Ten more rounds of chemo followed, ending in February. She began training to run a relay leg in the marathon.

“My training is slow, but steady. I’ll get up to my distance, then worry about speed,” Marsh says. She has reached one milestone, as the marathon’s top fundraiser for charity—$26,800 for Light of Life Mission, where she works as director of development.

“My faith is a huge part of this for me,” Marsh says. “When you have cancer as a young mom, it’s so intense. You have to really confront those fears with what you believe. I believe enough in God’s care for the poor to devote my career to it—do I believe enough in God’s care for me to trust him with all of this stuff? Bad things happen, but God is here and He’s going to use this for my good.”

Sandra Tolliver is a freelance writer, editor and public relations professional in Upper St. Clair.