I immediately think of Jonathan Tropper, even though I haven't finished any of his books yet... I think humor can be used in a lot of "serious" issues stories, but maybe not all. For example I have a hard time imagining humor in a story about sexual abuse, so I think you should choose your topic carefully and make sure that you, like chicken freak said, use the right kind of humor. That said, I read an autobiography once, about a woman who's been abused, had problems with drug addiction, been in prison and generally lead a very destructive life, but the entire book was written with such a sarcastic and humorous tone that both added to the tragedy but in the same time made it less of a "heavy" read, so that definitely worked for her.
