A carcinogen is an agent with the capacity to cause cancer in humans. Carcinogens may be natural, such as aflatoxin, which is produced by a fungus and sometimes found on stored grains, or manmade, such as asbestos or tobacco smoke. Carcinogens work by interacting with a cell's DNA and inducing genetic mutations.
A carcinogen is a specific chemical or physical agent that has the ability to cause cancer in individuals exposed to that agent. Interestingly, some carcinogenic agents are associated with increasing the risk of developing specific types of cancer. One good example is the carcinogen asbestos. Asbestos exposure, particularly to workers in industrial settings, has actually been strongly linked to the development of a specific type of lung cancer called mesothelioma. Importantly, once we have identified carcinogens, we can then go on to take specific measures to limit our exposure and so reduce the incidence of specific cancers associated with carcinogens, for example, limiting asbestos exposure.