Alex Trebek announced that he has been diagnosed with stage 4 pancreatic cancer. The “Jeopardy!” host shared the news on the show’s YouTube channel. "Normally the prognosis for this is not very encouraging, but I am going to fight this and keep working," Trebek said. Patrick Swayze, Steve Jobs and Luciano Pavarotti all died from the disease. The Canadian-born Trebek has hosted “Jeopardy!” for 35 years.