A diagnosis of cancer, usually the subject of serious, high-end tearjerkers, provides an unlikely launching pad for comedy in this beautifully played, precisely observed and surprisingly thoughtful buddy movie, which is based on a true story. Joseph Gordon-Levitt plays Adam, a struggling 20-something radio journalist whose life is rocked by the discovery of a malignant tumour. Adam soon finds, however, that being seriously ill has strange side effects: his girlfriend (Bryce Dallas Howard) becomes strangely distant, his already over-attentive mother (Anjelica Huston) tries to smother him even more and his blustering, insensitive best friend (Seth Rogen) simply pretends that none of this is happening. From these elements emerges a touching, plausible and, above all, very funny story of human vulnerability, with the wonderful double act of Gordon-Levitt and Rogen at its core. Gordon-Levitt deserves special credit for a likeable and fearless performance that never once slips into self-importance - or, more crucially, self-pity.