The young Chicago boy battling incurable cancer, whose request for birthday cards was shared around the world, passed away Sunday, according to his family.
Lucas "Bear" Cervone would have turned 6 in just under a week, and hundreds of people joined in the effort to fulfill his request for cards for his birthday on May 7.
In a Facebook post Sunday, the Cervone family asked for privacy, writing, "At 506pm CST, Lucas BEAR took his last breath. He is cancer free and no longer in pain."
The family gave Lucas one last birthday party in his final days.
Lucas was first diagnosed with pediatric leukemia in August 2012.
"He fought through three very long years and very intensive years of treatment and he won, he beat it," said Lucas' father, Anthony Cervone, in an interview this week.
But a short time later, he was diagnosed with another form of cancer, this one incurable. After a stem cell transplant in November 2015 and months in the hospital overcoming viruses, Lucas returned home to celebrate Christmas with his older brother, Franco, in February.
Then, just a few weeks ago, the Cervone family received the news it had been dreading: doctors found an incurable tumor near Lucas' heart.
"It has been decided that there are no further curative options," the family wrote April 25 on a Facebook page set up to support Lucas. "In simplest terms, there is nothing more we can do to fight this. We have started palliative chemo to attempt to slow the growth of the tumor. The tumor is wrapped around the pulmonary artery and is pressing on Lucas' heart."
The Cervone family then focused on making Lucas' remaining days his happiest.
"I want him to have the best quality of life I can give him until the end," his father said at the time
Lucas loved to read cards and received 500 letters from well-wishers for Christmas. His family reached out to supporters to try and surpass that number of his birthday.
That call was heard around the world, with hundreds of people, including 'Modern Family' star Ariel Winter, joining in to send cards to Lucas.
"He's my hero," said his mother, Rina Cervone. "I don't think I could ever be as strong as him."
"What we want to show him is his family will be here with him, as well as everyone else," Anthony Cervone added.