Today I’m going to talk about: carcinogen

Carcinogen, any chemical, biological, or physical agent that canpotentially be a cause of cancer. The term is most commonly applied tochemicals introduced into the environment by human activity. Researcherslabel a substance a carcinogen if it causes a statistically significantincrease in some form of neoplasm, or anomalous cell growth, when appliedto a population of previously unexposed organisms. The modes of cancerinitiation are still little understood, however, and efforts to establishthe carcinogenic hazards of substances have aroused great controversy. Thequestion of the usefulness of laboratory tests on animals in assessinghuman risks is particularly complex. The more recent development of short-term tests using cell cultures of microorganisms, however, is considered amajor advance in carcinogen research. Substances indicted as carcinogenic over the past few decades includethe pesticides DDT, Kepone, and EDB; the synthetic hormone DES; theartificial sweetener cyclamate; asbestos; and a wide range of otherindustrial and environmental substances. In addition, U.S. health officialshave identified the carcinogens in tobacco as the single most importantcause of cancer among Americans. The carcinogenic effects of various foodsare still under study.