(CNN) Alex Trebek is opening up about his pancreatic cancer battle.

Trebek has gone through chemotherapy and has to undergo it again, so he knows that he might not have a lot of time left to live, the "Jeopardy" host told ABC News.

But, he added, prayer and supporters have helped him feel a lot better since his diagnosis.

"I have learned something in the past year and it's this: We don't know when we're going to die," Trebek said. "Because of the cancer diagnosis, it's no longer an open-ended life, it's a closed-ended life because of the terrible survival rates of pancreatic cancer. Because of that, and something else that is operating here, people all over America and abroad have decided they want to let me know now, while I'm alive, about the impact that I've been having on their existence."

He added: "They have come out and they have told me, and my gosh, it makes me feel so good."

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