Carcinogenesis is the act of forming a cancer. Carcinogens cause mutations in our DNA which can lead to cancer. Therefore, chemicals that cause cancer are called carcinogens. Studies estimate that 2/3 of all cancers are caused by environmental carcinogens that could be eliminated. These carcinogens include tobacco, various chemicals, viruses, dietary factors, radiation sources and sunlight. How do carcinogens work? Chemical carcinogens, whether they are natural or man-made, cause injuries to the cell in the same basic manner. A carcinogen (radiation, pesticide, tobacco smoke, etc...) enters the tissue of an individual. Once a carcinogen enters the body, it is broken down into an unstable molecule. These chemically unstable molecules are called free radicals. These free radicals may directly interact with cellular material, like DNA. Free radicals can take nicks out of DNA and alter it. If the free radicals do interact with DNA and nick it, the DNA may become altered. This is how mistakes (or mutations) to our DNA may result. If you remember our discussion of DNA and cancer, it is the alterations in DNA that may eventually lead to cancer. Sometimes the free radicals interact with other areas of a cell, but the greatest impact can occur when a specific piece of DNA is damaged. Just imagine, every time we are exposed to a carcinogen, these free radicals form and bump into structures within a cell causing all sorts of damage. It is a miracle our bodies are able to prevent cancers as often as they do since we are exposed to so many carcinogens in our daily lives! Much of our exposure to carcinogens is from natural sources. For example, the sunlight we are exposed to every day is carcinogenic. The cells within our bodies have developed incredible mechanisms to compensate for carcinogens, but there is a limit to the amount of exposure they can take. If an individual is exposed to too many carcinogens, their body can become "overloaded with free radicals". In these instances, inevitably, something will wind up damaged. This section on carcinogens does not intend to point out everything that is thought to be carcinogenic, just some of the things you should be aware of. In some of our other articles, we focus on radiation and some of the earth's natural substances. In addition we will cover the man-made cancer causing agents that are polluting our food, water, and probably even the places we live and work in. It is a rising concern and pressure from everyday citizens that will keep the problems from getting worse. |
