BOSTON (CBS) — It was a touching moment for a father and daughter at a friend’s wedding.

Jessica Otto of Rehoboth and her dad, Peter, were invited onto the dance floor so that they could have their own father-daughter dance.

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Peter and Jessica Otto. (Photo credit: Denyse Dias and BelleRay Photography)

It’s a moment the two may not be able to share when Jessica gets married. That’s because Peter now has cancer for a fourth time and his family says he doesn’t have long to live.  At one point Jessica’s sister, Megan, also joined the two on the floor.

Peter and Jessica, joined by Megan, shed tears together on the dance floor. (Photo credit: Denyse Dias and BelleRay Photography)

Jessica and Peter have been riding the Pan-Mass Challenge together for 3 years. It’s an annual bike-a-thon that raises millions for Dana Farber Cancer Institute, where Peter is undergoing treatment.

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The Pan-Mass Challenge raised $47 million for the Dana-Farber Cancer Institute in 2016. (WBZ-TV)

Jessica tells us riding the PMC this summer will probably be the hardest thing she’s ever done. But she’s determined to ride to keep other families from going through the same heartbreak she is experiencing now.

Jessica says when she rides the PMC this August she’ll be thinking of her dad and their dance.

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Peter and Jessica talk about their 2016 and the 2015 Pan Mass Challenge bike rides on video.