Since the 1940s, scientists have isolated compounds and tested their ability to induce cancer. Substances which can cause cancer are known as carcinogen and the process of cancer development is called carcinogenesis. It was suspected early-on that carcinogens caused cancer indirectly, by causing DNA mutations. One early observation supporting this was that X-rays, which were shown to damage DNA, can cause cancer.  Since then, other types of radiation, many chemicals and some bacteria and viruses have been shown to cause cancer.  The topics covered in this section:

  • Environmental Agents and Cancer
  • Infections that Cause Cancer
  • Chronic Inflammation and Cancer
  • Detecting Carcinogens: The Ames Test
  • A Table of Carcinogens and Cancers