Former middleweight champion Daniel Jacobs announced his retirement from boxing Saturday via social media.
Jacobs, 37, lost to Shane Mosley Jr. last week, his second consecutive defeat. It was just Jacobs' second fight in nearly 4½ years. His previous bout was a split decision defeat to John Ryder in February 2022.
Jacobs, a New Yorker who was born in Brooklyn, dropped competitive decisions to Canelo Alvarez and Gennadiy Golovkin in his two most high-profile fights.
"I'm able to say I'm the first cancer survivor to be a boxing world champion, the biggest accomplishment I've ever [achieved]," Jacobs (37-5, 30 KOs) wrote. "Being able to inspire others with my story has always made me feel like my life meant more than just fighting inside the ring. A true miracle man."
Jacobs was diagnosed with osteosarcoma (a rare form of bone cancer) in May 2011 after he woke up one morning completely paralyzed. He underwent surgery to remove a large tumor wrapped around his spine and rebuild his spinal column.
After dozens of radiation treatments, Jacobs returned to the ring in October 2012. Nearly two years later, he won the WBA's secondary title at 160 pounds and made four defenses, including a first-round KO of Peter Quillin.
Jacobs later won the IBF middleweight title with a split decision victory over Sergiy Derevyanchenko in October 2018.
"It was a great honor to represent Danny throughout his entire career," manager Keith Connolly told ESPN. "He's the first boxer ever to win the world title after beating cancer and the only boxer ever to win a world title after being paralyzed from the waist down for several months.
"His story was truly remarkable and one of the greatest comeback stories in boxing history."