Scientists have studied the catastrophic genetic damage caused by smoking to different organs in the body and identified a number of different mechanisms behind the mutations caused by smoking. Scientists from the Wellcome Trust
Sanger Institute, Los Alamos National Laboratory, and other institutions have found that “smokers” who smoke a pack a day accumulate an average of 150 additional mutations per lung
The scientists found that “smokers” who smoke a pack a day accumulate an average of 150 additional mutations per lung cell per year. The study, published in the journal Science (paper title: Mutational signatures associated with tobacco
smoking in human
cancer) provides a direct association between the number of cigarettes smoked and the number of mutations in tumor DNA. The highest rate of mutations was observed in lung cancer, but tumors in other parts of the body also contained these smoking-associated mutations. This result explains why smoking causes a variety of human cancers. I. Over 5,000 tumors and 17 cancer types Smoking takes at least six million lives each year. If current trends continue, WHO predicts that there will be more than one billion tobacco-related deaths this century. Epidemiologically, smoking is associated with at least 17 types of human cancers, but until now, no one has identified the mechanism behind smoking causing many of these cancers. In this study, the researchers performed the first comprehensive analysis of smoking-related cancer DNA, examining somatic mutations and DNA methylation in more than 5,000 tumors (from 17 different cancer types), comparing tumors from smokers with those from patients who never smoked. They found DNA damage-specific molecular fingerprints in the DNA of smokers – called mutational
signature), and counted how many of these specific mutations occur in different tumors. The number of mutations varies by organ, with lung cells accumulating 150 in a year.
cell) to 150 mutations per year. This explains why smokers have a higher risk of developing lung cancer. Other organs are also affected. Specifically, smoking a pack of cigarettes a day causes an average of 97 mutations per cell per year in the larynx (larynx), 39 mutations per cell per year in the pharynx (pharynx), 23 mutations per cell per year in the mouth (mouth), 18 mutations per cell per year in the bladder, and 6 mutations per cell per year in the liver. Until now, scientists have not fully understood how smoking increases the risk of cancer in parts of the body that are not in direct contact with smoke. David Phillips, who participated in the study
Professor Phillips, who was involved in the study, explained: “Mutations caused by direct DNA damage occur mainly in organs that are in direct contact with inhaled smoke. In contrast, other cells in the body suffer only indirect damage, as smoking appears to affect key mechanisms in these cells that in turn alter DNA.” Ludmil, the study’s first author
Alexandrov, PhD, said, “Previously, there was a large body of epidemiological evidence linking smoking to cancer, but now we are able to actually observe and quantify the molecular changes in DNA caused by smoking.” Corresponding author Michael R.
Professor Stratton said, “Our study shows that the pathways by which smoking causes cancer are more complex than we thought. This study tells us that studying DNA in cancer could provide new ideas for understanding the development of cancer, and thus hopefully find ways to prevent it.” The deep “imprint” of smoking Of course, this study in Science is not the only evidence that smoking affects DNA. In a study published in Circulation: Cardiovascular
Genetics (title: Epigenetic Signatures of Cigarette
Smoking), scientists studied blood samples from 16,000 people and compared DNA methylation modifications in smokers (including ex-smokers). Importantly, these modifications persisted even after smoking cessation. Although most of the “modified” genes will be “restored” within 5 years of quitting, there are still some modified genes that remain “imprinted” with cigarettes 30 years after quitting. Fourth, let people helpless second-hand smoke In addition to active smokers, there are many people in the world who are harmed by second-hand smoke. Studies have pointed out that nearly 740 million people in China are exposed to the dangers of secondhand smoke every day, of which 182 million are children. Recently, scientists have also found a new mechanism behind the cancer-causing effects of secondhand smoke. A study published in PLOS ONE (paper title: Exposure of Human Lung Cells to Tobacco Smoke
Condensate Inhibits the Nucleotide Excision Repair
Pathway) suggests that tobacco smoke has a dual effect on DNA integrity: it not only damages DNA, but also inhibits a key process in DNA damage repair. Specifically, researchers at the University of Kentucky identified a new pathway by which tobacco smoke promotes the development of lung cancer: inhibition of a DNA repair process called nucleotide excision repair. Conclusion: Every time one of these studies comes out, many smokers will chortle, “Smoking is so harmful, let me smoke a cigarette to suppress it.” But jokes are jokes, but I still want to remind a word again: cherish life, smoking is harmful to health.