Carlos Laboy thought he was taking on a tough challenge when trying to raise funds this winter for his local youth theater program’s upcoming production of “Guys and Dolls.” But that fight now pales in comparison to the battle he now faces against a deadly disease.

In February, Laboy, who has enriched and emboldened hundreds of young lives as the longtime director of Mosholu Montefiore Community Center’s Stagekids theater program, was diagnosed with a form of cancer called Mantle cell lymphoma, a non-Hodgkins lymphoma.

The Bronx native recently completed his third round of chemotherapy treatment and doctors are optimistic about his chances. Laboy says he hopes to return to work by October.

“Anything can happen,” Laboy said from his hospital room at Montefiore Medical Center, where he was admitted on Sunday night after his fever broke 100. “I’m staying positive.”

The diagnosis and symptoms leading up to it “came out of nowhere,” Laboy said. Over the winter he had begun to feel some chest pain, so he quit smoking cigarettes. The chest pains continued. Then, one day in early February, he noticed a lump sticking out of his neck the size of a “baby’s fist.”

Montefiore doctors kept him under observation for four days, but at first they didn’t find anything cancerous. But two days after they let him go, he became very sick again and returned to Montefiore, where he would stay for the next six weeks. During that time, doctors performed another biopsy and identified the cancer.

After the diagnosis, Laboy immediately thought about his kids and his program’s upcoming shows. He asked when he could return to work. Doctors told him work was out of the question for at least eight months while he underwent treatment.

Although slightly frustrated, Laboy has remained upbeat.

“His attitude is marvelous,” said Geiddy Munoz, a former student of Laboy’s who became Laboy’s stage manager and is now assuming directing responsibilities in his absence. “I saw him when he was told and he was like a kid finding something new and playing with it.”

While Laboy isn’t attending rehearsals, he’s still shaping the upcoming production “Guys and Dolls,” which is scheduled for May 28 and 29 at the PS 8 auditorium in Bedford Park. During his extended hospital stay, students came by to ask for advice and tips. Plus, he’s constantly e-mailing his students with directions and ideas. 

Munoz said she feels a certain amount of pressure trying to fill Laboy’s shoes. “I’m trying to live up to Carlos’ vision for what he wanted to do with the show.”

Besides Stagekids, Laboy also runs a youth broadcasting program through the community center called Teen 2 Teen where students learn how to produce their own news show.

That program is nearly running itself, Laboy said. “I have such a great group of kids.”

Laboy said his hospital room swelled with more than 100 cards from students and parents.

He also said he’s receiving a tremendous amount of support from his “family over there” at the Mosholu Montefiore Community Center. While Laboy waits for Medicaid to come through, the center paid for a month of his rent.

“Carlos is such a sweet person,” said the center’s executive director, Don Bluestone. “His work at the center has been his life. It’s probably why it’s been hard for him to deal with [being sick and away from work]. He’s really part of our family.”

A lifelong theater personality, Laboy laughed between coughs on Monday afternoon. He said he wants everyone to remember two things while he’s fighting the battle of his life: he’s staying positive and “the show must go on.”