• Learn about cancer
  • What is cancer?
  • What causes cancer?
    • DNA damage and its consequences
    • Carcinogens
    • Lifestyle issues
    • Inheritance and familial cancer
    • Other risk factors
  • Detecting cancer
  • Cancer treatment
• Cancers at a glance
• Research highlights
• About cancer research
• Understanding 'risk'
• Our history and achievements

Carcinogens

During the course of a day, we are continually exposed to things that damage our DNA. This damage needs to be repaired by the DNA repair proteins found in each of our cells. Things that damage DNA are called carcinogens, and they include:

• Tobacco
• Car exhaust fumes
• The sun
• Natural and man-made radiation
• Asbestos

Many of these things cause damage because they react with the molecules in our cells to form free radicals. Free radicals are highly damaging molecules, and can wreak havoc on the sensitive machinery inside a cell. Cancer Research UK is funding research into understanding exactly how these carcinogens damage or DNA.

But it is a mistake to believe that exposure to carcinogens is the only cause of cancer. In almost all cases, carcinogens are contributing factors, but there is a whole host of other factors at work. For example, tobacco smoke is a powerful carcinogen, but not all smokers get lung cancer, and some people with lung cancer have not been exposed to tobacco smoke.