The football world stood behind Giants co-owner John Mara after he revealed his cancer diagnosis on Monday. 

Mara made the surprise announcement in a statement, saying that he had “recently been diagnosed with cancer” and that he was “feeling strong and optimistic, and I’m committed to seeing this through to a positive outcome.”

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The news led to an outpouring of support for Mara, including from several former members of the Giants organization. 

“Sending strength, support, and prayers to John Mara. Your leadership and grit inspire everyone around you. No one fights cancer alone. It takes a team and always proud to be on yours,” former two-time Super Bowl-winning Giants coach Tom Coughlin said in a statement. 

Former Giants defensive end Osi Umenyiora recalled Mara’s kindness when he suffered a knee injury that knocked him out for the 2008 season. 

“Only one person from the Organisation came to the hospital to see me. John Mara,” he wrote in a post on X. “I couldn’t believe it was him, I just started crying. And he just sat there until I fell asleep. Didn’t say a word. He will beat this for sure.”

Former NFL wide receiver Antonio Brown wrote in a post on X that he was “hoping for the best for John Mara.” 

The Jets said that their “thoughts are with John Mara and his family” and that the organization was “Sending strength, support and well wishes.”

A number of other NFL teams sent similar messages, including the Broncos, Texans and 49ers.

It was not announced what type of cancer Mara has or what stage it was. 

Mara had been on hand at MetLife Stadium on Sunday when the Giants beat the Chargers for their first win of the season, snapping a three-game losing streak to start the season.