Researchers say intake of twenty cigarettes daily per annum equals 150 lung cell mutations

Emobileclinic Researchers Corner 

The Journal of Science has published the findings of researchers who discovered the amount of cigarettes smoked and the amount of mutations in the DNA of tumour and concludes that smoking is a killer. Cigarette smoking has serious negative effects on human’s health. According to a release by the World Health Organization (WHO), close to 6 million deaths are recorded annually due to smoking-related illnesses. The agency projected that if the trends continue, about 1 billion tobacco-related deaths will be recorded this century.
Smoking has been associated with several irreversible damages to a number of body organs and sparks mutations in DNA via a number of mechanisms. Presently, smoking has been associated with 17 types of cancer; however, the genetic mechanisms behind this have not been known.
The researchers conducted investigation on the DNA of 5,000 tumors where they compared tumors from nonsmokers with tumors from smokers and examined any genetic differences. The analysis provided an understanding of the molecular fingerprints of smoking-related DNA damage. They were able to identity these mutational signatures and know the number of mutations in each tumor.
The finding revealed that smoking a pack of cigarettes daily led to a predictable average number of mutations in the lungs in a year. According to Dr. Ludmil Alexandrov, “before now, we had a large body of epidemiological evidence linking smoking with cancer, but now we can actually observe and quantify the molecular changes in the DNA due to cigarette smoking” and that “with this study, we have found that people who smoke a pack a day develop an average of 150 extra mutations in their lungs every year, which explains why smokers have such a higher risk of developing lung cancer.”
The team also invented a mechanism that shows the effects of cigarettes on mutations in other organs. The team discovered that a pack daily resulted in:
§ 97 mutations in each cell in the larynx
§ 39 mutations in each cell in the pharynx
§ 23 mutations in each cell in the mouth
§ 18 mutations in each cell in the bladder
§ 6 mutations in each cell in the liver.
As said earlier, it has been difficult showing how mutations affect organs of the body apart from the lungs. Kudos must be given to the researchers for discoveries ways in which tobacco can develop mutations in different tissues and organs.
Out of the five distinct processes by which DNA is damaged by tobacco smoke, the most proliferated was the one already discovered in other nonsmoking-related cancers. The team found that smoking speed up a cellular clock that prematurely mutates DNA. According to Prof. Sir Mike Stratton, “this study of smoking tells us that looking in the DNA of cancers can provide provocative new clues to how cancers develop and thus, potentially, how they can be prevented.”

Similarly, Dr. Alexandrov said “this study has shown that molecular profiling of cancer patients can be used to identify the mechanisms by which different carcinogens cause cancer. We are planning future studies to reveal the mechanisms by which other known epidemiological factors cause cancer. For example, we are currently working on elucidating the mechanisms by which obesity causes cancer.”