Hey, did you hear the one about my metastatic tumor? Comedy and cancer may mix about as well as champagne and toilet cleaner, but along comes the film "50/50" to attempt just that.

This may sound like some "South Park"-esque experiment in poor taste and offensiveness, but "50/50" betrays entirely different intentions: Its story derives from the actual experiences of screenwriter Will Reiser, who was diagnosed with a possibly fatal tumor when he was only 25 years old. One of the film's stars, Seth Rogen, and one of its producers, Evan Goldberg, were friends of Reiser's from the days they all worked on the U.S. version of "Da Ali G Show"; they encouraged Reiser to turn his experience into a script, and no doubt their clout (after working on "Superbad," "Pineapple Express" and "The Green Hornet") got a studio to take a chance on this potential bummer of a topic.

"50/50" stars Joseph Gordon-Levitt as a fictionalized version of Reiser named Adam, a guy who has an artist girlfriend (Bryce Dallas Howard), a satisfying job with public radio and all his life ahead of him. Hell, he even jogs. Then a visit to the doc for recurring back pain winds up with the diagnosis of a spinal tumor, and his life quickly becomes a harsh routine of chemotherapy and night sweats. His girlfriend makes a half-hearted effort to support him, but quickly bails, leaving him mostly supported by his oafish buddy Kyle (Rogen), who's always getting into Adam's medical marijuana; his neurotic mother, Diane (Anjelica Huston); and his awkward newbie therapist, Katherine (Anna Kendrick).