Common Name

Listen up, buttercup. The joke is all about wordplay, see? It asks what the most common name for cancer patients is. The answer is "Luke," which sounds like "leukemia," a type of cancer. It's funny 'cause it uses a common name to make a grim situation sound a little lighter. As for you not getting it, well, I'm not surprised. You probably still think the Earth is flat, ya goof!