Abstract

Cancer affects almost one in two persons worldwide, making it a devastatingly common disease. However, each cancer arises from an individual cell, of which there are some hundred thousand billion in each human. So, while cancer is a common disease, it is nonetheless a vanishingly rare phenomenon. Furthermore. Since cancers arise by random mutation in affected cells, every cancer is different from every other. Indeed, as random mutation continues during cancer development and progression, it is possible that every cancer cell in every cancer in every patient is unique. Modern genomic technologies have confirmed these facts and exposed cancer as a bewilderingly and endlessly complex and diverse. How can we possibly understand, let alone treat, such a protean disease? I will present evidence that this apparent complexity may be a distraction. Despite their many differences, cancers are remarkably similar to each other and share remarkably common underlying features and mechanisms. The clue to understanding these mechanisms comes from an appreciation that cancers are aberrant versions of normal processes that serve to maintain and protect us during our lives. These “friends” only become our “enemies” when they are hacked by cancer-causing mutations. It even seems that cancers carry within them mechanisms to reverse themselves, perhaps opening up an entirely novel approach to cancer treatment.