When Dr. Nick Mondek learned his cancer had returned this spring, he didn’t know that his 10-year-old son Stephen would eventually become his lifesaving hero.
“Stephen is proof that real-life heroes come in all shapes, sizes and even ages,” Mondek told ABC News. “They may be right in front of us, and we don’t even know it, and in one act of bravery and courage, they can completely alter your life.”
Courtesy of the Mondek family – PHOTO: Dr. Nick Mondek with his sons John and Stephen.
Mondek, a Los Angeles anesthesiologist and father of two, had previously undergone chemotherapy and a stem cell transplant for acute myeloid leukemia, a type of cancer of the blood cells. His older brother Dave had donated his stem cells to him in 2022.
This time, Mondek told ABC News he turned to extended family members and the National Bone Marrow Registry, but he didn’t find any suitable matches.
“It was a dismal prognosis, and I needed a donor immediately, and there was no one available,” Mondek said.
People with acute myeloid leukemia typically need treatment sooner than later, as the cancer may worsen quickly, according to the National Cancer Institute. Doctors may treat this type of cancer in a variety of ways, including with chemotherapy, radiation and stem cell transplants, and for Mondek, he said another stem cell transplant ended up being his last option after undergoing chemotherapy and radiation.
Courtesy of the Mondek family – PHOTO: Dr. Nick Mondek with his wife Danielle Boyer.
Mondek and his wife Danielle are parents of sons Stephen, 10, and John, 6, and during a particularly dark period in June, Mondek said he thought of his family. He also remembered a good friend who had lymphoma, another type of cancer that impacts the lymphatic system, had found a donor in his own 18-year-old son.
“I wasn’t sure if my son would be an option, but I did bring it up to my physician,” Mondek recalled. “I said, ‘Could a 9-year-old who’s only 70 pounds potentially get us enough stem cells to make this a successful transplant?’ And that’s when the conversation started.”
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As a doctor and parent, Mondek said starting the conversation with his young son was “nerve-wracking” but ultimately led to the best outcome.
“The biggest factor that I had in my brain was [that] I don’t want him to feel forced. I don’t want him to feel obligated,” said Mondek. “So I didn’t even tell him that we were down to him as our last option. I told him we were still looking at candidates and [said], ‘Would you consider potentially getting tested to see if maybe you could be a donor?’ And he was all for it.”
Mondek describes his son Stephen as “very shy” and “quiet” but altruistic and someone who is always looking out for others.
“Without batting an eye, he said, ‘When do we go?'” Mondek said.
Courtesy of Cedars-Sinai – PHOTO: Dr. Nick Mondek’s son Stephen, now 10, donated stem cells to his dad, who had a relapse of acute myeloid leukemia in April 2025.
Doctors at Cedars-Sinai successfully extracted stem cells from Stephen, and Mondek received his second stem cell transplant on July 30.
The proud dad called his son his hero and a tough boy who “never complained once.”
“He didn’t have to put on a cape or leap buildings in a single bound. Instead, he put on a hospital gown and gave me hope,” Mondek said. “I’m not just honored to call this boy my son, I am just as honored to call him my hero.”
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Stephen told ABC News’ Los Angeles station KABC that he had support from his peers as well.
“It feels good to do that, because all my friends are proud of me,” the 10-year-old said.
Both father and son are now out of the hospital, and Mondek said Stephen is doing great.
Courtesy of Cedars-Sinai – PHOTO: The Mondek family – mom Danielle Boyer, John, Stephen, and dad Dr. Nick Mondek.
“Within three or four days, he was already back at baseball practice,” said Mondek.
Mondek said he’s on a long road to a new normal, but currently, his prognosis looks promising.
“They did a blood test last week for the first time to screen my blood for any of the DNA of my leukemia cells, and they couldn’t find any,” said Mondek. “So, as of right now, I’m still in remission, and there’s no sign of cancer.”
