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Alex Trebek, the longtime "Jeopardy!" host, revealed Wednesday that he has been diagnosed with stage 4 pancreatic cancer.

Trebek, 78, said in a video posted to YouTube he will attempt to finish out this season of "Jeopardy!"

"Just like 50,000 other people in the United States each year, this week, I was diagnosed with stage 4 pancreatic cancer," he said.

"Now, normally, the prognosis for this is not very encouraging, but I’m going to fight this, and I’m going to keep working, ” he said in the video. "And with the love and support of my family and friends and with the help of your prayers also, I plan to beat the low survival rates statistics for this disease."

Trebek has hosted the show since 1984. He took a leave of absence in January 2018 after surgery to remove blood clots from his brain.

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In October 2018, he renewed his contract with Sony Pictures Television to continue as host of the quiz show through 2022.

Ken Jennings, who holds the record for the longest winning streak on "Jeopardy!" said on Twitter that Trebek is an institution like Walter Cronkite.

"I’ve said this before but Alex Trebek is in a way the last Cronkite: authoritative, reassuring TV voice you hear every night, almost to the point of ritual," Jennings said. "One thing I know for a fact: Alex is very aware of how much he means to millions of people, and how we will be pulling for him...I hope that’s a comfort."

Pat Sajak, the host of "Wheel of Fortune," said he "would never bet" against Trebek.

"The Sajak family is deeply saddened to hear of Alex Trebek’s struggle with cancer," he said in a tweet. "Our hearts go out to him and his family. But there is no one I know who is stronger and more determined, and I would never bet against him. We, and the entire country, are pulling for you, Alex."

The Sajak family is deeply saddened to hear of Alex Trebek’s struggle with cancer. Our hearts go out to him and his family. But there is no one I know who is stronger and more determined, and I would never bet against him. We, and the entire country, are pulling for you, Alex. — Pat Sajak (@patsajak) March 6, 2019

Sony Pictures Television Chairman Mike Hopkins said Trebek has the company's support "as he tackles this challenge."

"If anyone can beat this it's Alex," Hopkins said. "He has our full support as he tackles this challenge head-on."

According to the Hirshberg Foundation for Pancreatic Cancer Research, pancreatic cancer has the highest mortality rate of the major cancers with 91 percent of patients dying within five years of a diagnosis. It is the third leading cause of cancer-related deaths.

About 56,770 people will be diagnosed with pancreatic cancer in 2019, according to the American Cancer Society. About 45,750 people will die of the disease this year.