Variation in cancer risk among tissues can be explained by the number of stem cell divisions.
Do you think doing all the right things will prevent the worst? A new study suggests that despite your hard work, it may be more up to chance. Researchers at the Johns Hopkins Kimmel Cancer Centre have found thar two-thirds of cancer occurrences in certain tissue types result from random mutations. The remaining percentage comes from a combination of lifestyle and environmental factors.
The study was led by physicians Dr. Cristian Tomasetti and Dr. Bert Vogelstein. Their article appeared in the journal Science, under the title “Variation in cancer risk among tissues can be explained by the number of stem cell divisions.” The method used in the study involved plotting the normal occurrences of different types of cancers against the approximate amount of usual stem cell divisions in a given tissue. The researchers found that there was a strong correlation “that extended over five orders of magnitude,” quoted Science. What this means is that the study suggests a stronger role for mistakes in DNA replication in the development of cancer. However, it is important to stress the fact that this study does not state that all cancers fall under this statistic. Only certain tissue types were the focus of the study, so only a subcategory of cancers, such as cancers in the digestive tract, would be considered in this statistical model.
On the news release page for the Johns Hopkins Kimmel Cancer Centre, the researchers described their study as follows: “Our results would be equivalent to showing a high correlation between lengths of trip and getting into an accident. Regardless of the destination, the longer the trip is, the higher the risk of an accident.” This means that the trip, described by the researchers, is analogous to the number of times the cell divides in a given tissue. Tissues that have to be replaced often would have a higher rate of mutation than tissues that do not have to replaced often.
Cancer is a term used to describe a wide range of diseases which occur when the normal functioning of the cells goes wrong. Genes play a big role in cellular division. Eventually the cell loses its normal functioning ability and turns rogue. The latter will continue to divide and spread, displacing functioning issue with cancer tissue. This leads to the loss of function of the surrounding tissues and it affects the body as a whole. There are over 100 types of cancers known and it is the leading cause of death in Canada, which comprised 29.9 per cent of deaths in 2011 according to Statistics Canada.
All cancers are caused by a mixture of genetics, lifestyle and environment. It is important to maintain good health because it still contributes to your likelihood of developing cancer and other harmful diseases. In the press release, the researchers compared the “trip taken” to be made worse by the environmental factors: “The road conditions on the way to the destination could be likened to the environmental factors in cancer. Worse conditions would be associated with a higher the risk of an accident.” So, although your cells may develop into cancer cells due to the underlying flaws, lifestyle choices make the trip more likely to end up in an accident.
