I practically fall out of my seat every time I watch this scene. Cinematic genius of the highest order.
Part of what makes this line so hilarious for me, by the way, is the fact that while reading for this scene the actress asked the director, Tommy Wiseau, if this revelation, which comes out of literally nowhere, has any impact later in the story, and he just told her not to worry about it. As it turns out, her cancer diagnosis is
never brought up again at any point in the film! So to think that the actress was reciting that line while feeling just as befuddled about this bombshell as the audience feels in that moment only adds to the comedic effect.