Following news that Alex Trebek has been diagnosed with stage 4 pancreatic cancer, celebrities and former "Jeopardy" contestants took to social media to share messages of support for the longtime "Jeopardy" host.
"Wheel of Fortune" host Pat Sajak
"Wheel of Fortune" host Vanna White
"Jeopardy" champ Ken Jennings
Walt Disney Company CEO Bob Iger
Dr. Phil McGraw
Canadian Prime Minister Justin Trudeau
Recent "Jeopardy" contestant Brad Rutter
Children's television program "Arthur"