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 / Updated  / Source: TODAY
By Alexandra Zaslow

Sean Bartolucci celebrated becoming cancer-free in the best way possible.

The 13-year-old boy from Camp Hill, Pennsylvania, visited the Philadelphia Museum of Art on Sunday to run the famous "Rocky" steps — not one, but two at a time.

Sean Bartolucci celebrated beating cancer by running the iconic 'Rocky' steps at the Philadelphia Museum of Art.Courtesy of Michele Bartolucci

The teenager was joined by family and friends eager to cheer him on.

“Everyone who has been through Sean’s journey with us wanted to let him know they’ll have his back and will be behind him forever, with or without cancer,” Michele Bartolucci, Sean’s mom, told TODAY.com.

Sean was diagnosed with neuroblastoma in February 2014 and has since undergone countless chemotherapy and radiation treatments, multiple surgeries and a stem cell transplant.

Sean posed with the 'Rocky' statue.Courtesy of Michele Bartolucci

During his treatment, Sean made a pledge to run up the steps made famous in the 1976 movie "Rocky" when he became cancer-free, and his family was thrilled to see that dream come true.

“The last 18 months have been a war inside his body and to see this kid run up the steps, healthy, was just remarkable,” Bartolucci said.

Sporting neon shirts reading, “Sean’s a fighter,” the teenager's supporters started out running behind him, assuming he’d take it slow. But as soon as he took the first step, he was off.

Family and friends came out to support the 13-year-old, who has battled cancer for 18 months.Courtesy of Michele Bartolucci

“The day was just filled with emotion; when we got to the top and looked back at the sea of bright neon shirts, we were just like ‘wow,’” Bartolucci said. “He couldn’t stop smiling.”

Over the last year and a half, when Sean wasn’t in the hospital, he was taking online classes to catch up with his peers. He’s excited to get back to school in the fall at Camp Hill Middle School.

“He’s truly a fighter and I don’t think I could be more proud as a parent,” Michele said.