Mending and malignancy

摘要

The familiar sensation of heartburn — whether from greasy food or too much coffee — is caused by acid reflux from the stomach into the oesophagus and is probably harmless on an occasional basis. On the other hand, persistent heartburn can indicate lasting damage to the lining of the oesophagus, resulting in changes in the cellular architecture of the epithelium and an increased incidence of the lethal cancer oesophageal adenocarci-noma. Increased cancer risk is also associated with other types of chronic tissue injury, including those caused by toxins (such as alcohol, cigarette smoke and solvents), chronic infection of Helicobacter pylori arid other pathogens, and inflammatory conditions, such as sclerosing cholangitis and inflammatory bowel disease. Genetic mutations are thought to be at the root of cancer, but although some of these injurious agents are mutagens, others are not. How, then, does injury contribute to cancer risk?