"Jeopardy!" host Alex Trebek can take much solace in the well wishes he's getting over social media for a successful fight of his advanced cancer. The 78-year-old Canadian native announced in a video posted on YouTube that he has stage 4 pancreatic cancer. In the video, Trebek said that he will continue working on the show while undergoing treatment and vowed to beat the disease's low survival rate. Thousands of people on social media reached out to share their favourite moments from the show. Fellow game-show host and friend "Wheel of Fortune's" Pat Sajak also expressed his sadness over the news on social media. Among the messages of support, former contestants shared pictures and their memories from the show.