Cancer pathogenesis is traceable back to DNA mutations that impact cell growth and metastasis. Substances that cause DNA mutations are known as mutagens, and mutagens that cause cancers are known as carcinogens. Particular substances have been linked to specific types of cancer. Tobacco smoking is associated with lung cancer and bladder cancer. Prolonged exposure to asbestos fibers is associated with mesothelioma.
Many mutagens are also carcinogens, but some carcinogens are not mutagens. Alcohol is an example of a chemical carcinogen that is not a mutagen. Such chemicals are thought to promote cancers through their stimulating effect on the rate of cell mitosis. Faster rates of mitosis leaves less time for repair enzymes to repair damaged DNA during DNA replication, increasing the likelihood of a genetic mistake. A mistake made during mitosis can lead to the daughter cells receiving the wrong number of chromosomes.
Decades of research have demonstrated the strong association between tobacco use and cancers of many sites, making it perhaps the most important human carcinogen. Hundreds of epidemiological studies have confirmed this association. Further support comes from the fact that lung cancer death rates in the United States have mirrored smoking patterns, with increases in smoking followed by dramatic increases in lung cancer death rates and, more recently, decreases in smoking followed by decreases in lung cancer death rates in men.
Many mutagens are also carcinogens, but some carcinogens are not mutagens. Alcohol is an example of a chemical carcinogen that is not a mutagen. Such chemicals are thought to promote cancers through their stimulating effect on the rate of cell mitosis. Faster rates of mitosis leaves less time for repair enzymes to repair damaged DNA during DNA replication, increasing the likelihood of a genetic mistake. A mistake made during mitosis can lead to the daughter cells receiving the wrong number of chromosomes.
Decades of research have demonstrated the strong association between tobacco use and cancers of many sites, making it perhaps the most important human carcinogen. Hundreds of epidemiological studies have confirmed this association. Further support comes from the fact that lung cancer death rates in the United States have mirrored smoking patterns, with increases in smoking followed by dramatic increases in lung cancer death rates and, more recently, decreases in smoking followed by decreases in lung cancer death rates in men.
No comments:
Post a Comment