NO matter what happens on “The Amazing Race,” father-son duo David and Connor O’Leary of Salt Lake City have already won the biggest challenge of their lives. Both men have faced cancer – and won!

“We’ve shared a lot, including cancer,” said dad David, 58. “Three years ago at this time, he (Connor) was undergoing chemotherapy.

“To be able to be healthy and be sitting here to do this together is just an unbelievable opportunity.”

CONNOR, A 21-YEAR-OLD profes­sional cyclist, was diagnosed with testicular cancer on June 21, 2010, just three days after his 19th birthday.

He’d been experiencing swelling in his left testicle for almost six months. David, who had suffered from prostate cancer two years earlier, took Connor to his urologist.

The physician soon confirmed the devastating news that Connor had cancer.

“The irony is that because Dave had cancer earlier, he was able to help save his son’s life,” a show insider told The ENQUIRER. “The pair have been through thick and thin together. That’s why they decided to compete on ‘The Amazing Race.’”

The 22nd season of the Em­my-winning CBS reality adventure show premieres on Feb. 17. David, Connor and their fellow competitors will traverse more than 30,000 miles in nine countries across five continents, visiting such exotic locales as Bora Bora and Botswana!

Win or lose, the men hope their participation in the gruel­ing challenge will show other cancer sufferers that “anything is possible.”

Connor noted: “Two cancer survivors can come back from incredible odds and do hard things.