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Smoker's cancer cell mutation Multiple organ damage from tobacco consumption
Smoking harms your health and can cause cancer - this is well known. Scientists from the US and England have now investigated the genetic damage caused by the blue haze and came to a drastic conclusion: Because the tobacco smoke harms not only the lungs, but also leads to dangerous mutations in other organs.
150 mutations in each lung cell
People who smoke a pack of cigarettes a day cause an average of 150 mutations per year in each lung cell. This shows a study published on Thursday in the journal "Science", in which the cancer risk for smokers was examined. Researchers at the National Laboratory in Los Alamos (New Mexico, USA) and the Wellcome Trust Sanger Institute (Hinxton, England) had studied the genome of 5,000 tumors for the project. They compared those of smokers with those of people who had never smoked, according to the Wellcome Trust Sanger Institute.
A new study clearly shows that smoking not only harms the lungs massively, but also leads to dangerous changes in other organs. (Image: Andrey Popov / fotolia.com) The researchers discovered in the genome of the smoker's tumors certain molecular fingerprints of DNA damage ("mutation signatures") in the smoker's DNA and counted how many of these specific changes in the genome were found in the various tumors. It was found that there is a direct correlation between the number of mutations in the tumor DNA and the number of cigarettes smoked.
Genetic changes even in distant organs
The highest rates were identified by researchers with around 150 mutations per cell in the lungs. But in other parts of the body tumors also contained mutations associated with smoking. According to the statement, this explains how tobacco use causes different types of cancer. Thus, one pack of cigarettes per day per year results in an average of 97 mutations in each larynx cell. In the pharynx occur on average 39 and in the mouth 23 changes. Even organs such as the bladder and the liver, which have no direct contact with tobacco smoke, are affected in the study with 18 or 6 mutations.
"This study provides new insights into how tobacco smoke causes cancer," first author Ludmil Alexandrow of the National Laboratory is quoted in a statement from his institute. "Our analyzes show that tobacco smoking causes mutations that lead to cancer through several different mechanisms. Tobacco smoking damages DNA in organs directly exposed to smoke and also speeds up a variable cell clock in organs exposed to both direct and indirect smoke, "he continued.
Study highlights need for preventive measures
According to Heidelberg cancer expert Martina Pötschke-Langer, the study reinforces existing knowledge. "But the application of knowledge must follow in politics and in parliament," said the expert to the news agency "dpa". Accordingly, from Pötschke-Langer's point of view, preventive measures such as an increase in tobacco tax, a ban on advertising tobacco products and stronger protection against non-smokers are required.
Tobacco smoke contains 7,000 chemicals
According to the study, tobacco smoke is a complex mixture of more than 7,000 chemicals, including more than 70 known to cause cancer (carcinogens). Earlier epidemiological studies have linked smoking to increased risk for 17 different types of cancer - including tumors in tissue that is not directly exposed to smoke. In the new study, the research team identified more than 20 mutagenic signatures in these species and identified five of them as having smoker cancer.
One signature, the so-called "signature 4", was found mainly in DNA damaged by direct tobacco smoke exposure, such as the lung. The "signature 5" was thus found in all types of cancer that are caused by smoking. Other signatures would reinforce the authors' theory that smoking increases the risk of multiple cancers by increasing the total number of mutations. However, the authors note that for some of the variants the underlying mechanisms are still unclear.
Cigarette smoke is more complex than expected
"Our research shows that the way tobacco smoking causes cancer is more complex than we thought. In fact, we do not fully understand the underlying causes of many types of cancer, "said Mike Stratton of the Wellcome Trust Sanger Institute, according to the announcement from his institute. "But this smoking study tells us that looking at the DNA in cancer can provide new, provocative clues about how cancer develops and can potentially be prevented," Stratton continued.
From the point of view of the cancer expert Pötschke-Langer, the study is also of particular significance because of its scope: "This study will certainly attract a great deal of attention," said the former head of the Cancer Prevention Unit of the German Cancer Research Center (DKFZ) to the news agency.
Smoking is the biggest preventable risk to health
In Germany, according to the Federal Ministry of Health, a total of 28 percent of the adult population aged 18 or over smoke. Men smoke 31 percent more frequently than women (24 percent smoke). There is a clear decline in the number of adolescents. In the last fifteen years, the proportion of 12- to 17-year-olds has dropped from 27.5 percent in 2001 to 7.8 percent in 2015.
According to the ministry, around 120,000 people die each year as a result of tobacco use. This is still the largest avoidable health risk in this country. For example, a recent study showed that smoking significantly lowers average life expectancy. Lung cancer deaths in women also increase dramatically.
Quitting smoking quickly brings positive effects
Therefore, banning cigarettes from your own life is always a good idea - no matter how old you are. Above all, giving up smoking requires a firm commitment and consistent renunciation. But the success is quickly noticeable and the risk for most cancers drops significantly after a few years as a non-smoker. (No)