Jeopardy! host Alex Trebek is going through another round of chemotherapy to treat stage 4 pancreatic cancer. Trebek made the announcement on Tuesday's Good Morning America. Trebek said his doctors ordered the treatment after his "numbers went sky high" and he lost "about 12 pounds in a week." For a while, Trebek was doing ok and only needed immunotherapy. Trebek also said, "Cancer is mysterious in more ways than one." Do you have someone in your life dealing with cancer? How has it affected you, your family, your friends?