Editorial

In summary, identification and study of the RB tumor suppressor has provided an essential knowledge basis for delineating endogenous mechanisms that protect against tumor formation. Significant advances in our understanding of RB funtion have unexpectedly revealed that its tumor suppressive activity extends to many disparate cellular pathways and that RB function is often tissue specific. Current challenges remain on how to harness this information and apply this detailed understanding of RB action to the improvement of cancer diagnosis and therapy.