Paul Scotting and Penny Howard outline the known agents and mechanisms that can trigger carcinogenesis, including infectious and environmental factors

To understand how and why cancer occurs, we need to understand carcinogenesis, the process by which agents called carcinogens cause damage to genes and the nature of the damage that leads to mutations. Similarly, knowledge of the mutations that result in cells becoming cancerous allows us to understand why certain therapeutic strategies might work, while others would not. A glossary of the terms used in this article is provided on page 27.