Ever made a joke about your bipolar to someone else and they become so uncomfortable that the jovial atmosphere becomes incredibly awkward? It's crazy. It even happens with my fiance. I'm just over here cracking jokes (that I believe to be pretty funny ) and all I get in response is an awkward blank stare and a quick subject change. I don't know, maybe they would be just as bad with cancer jokes, but I think if the person afflicted with whatever their joking about can use humor to deal with it, then laugh with them. It's okay, really.