HealthDay News — Tobacco smoking causes mutations that lead to cancer by multiple distinct mechanisms, according to a study published in the November 4 issue of Science.
Researchers from the Los Alamos National Laboratory in New Mexico, the Wellcome Trust Sanger Institute in England, and other institutions analyzed 5,243 cancer tumors from smokers and nonsmokers.
“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,” co-lead author Ludmil Alexandrov, PhD, from the Los Alamos National Laboratory, said in a Wellcome Trust news release. “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.”
Tumors from other parts of the body also contained smoking-related mutations, the scientists found. For example, smoking a pack a day led to a yearly average of 97 mutations in each cell in the larynx, 39 mutations for the pharynx, 23 mutations for the mouth, 18 mutations for the bladder, and six mutations in every cell of the liver.