A study published Thursday accurately measures the devastating genetic effects of smoking for the first time. Smoking a pack of cigarettes per day causes an average of 150 mutations per year in lung cells, researchers have determined. By analyzing and comparing tumors, they identified several mechanisms by which smoking damages DNA.
This study published Thursday in the American magazine Science accurately measures for the first time the devastating genetic effects of cigarette smoking, not only in the lungs, but also in other organs not directly exposed to smoke. Epidemiological studies show that smoking contributes to at least 17 types of human cancers, but, until then, it had not been determined how smoking caused these tumors, indicate these researchers of the British Wellcome Trust Sanger Institute and Los Alamos National Laboratory U.S..
The greatest number of genetic mutations caused by tobacco have been observed in lung tissue. But other parts of the body also bore the signature of these DNA alterations, explaining how smoking causes different types of cancer.
7000 CHEMICAL SUBSTANCES IN THE CIGARETTE
The cigarette contains more than 7000 chemical substances different types, of which more than 70 are known to be carcinogenic, indicate these researchers, pointing out the complexity of the interactions with the organism.For this first extensive analysis of cancerous DNA linked to tobacco, these researchers examined more 5000 tumors, comparing cancers of smokers with similar cancers of people who have never smoked.
The researchers concluded that tobacco causes a large number of additional genetic mutations in lung cells. In other organs, the study reveals that a pack of cigarettes per day causes an average of 97 more mutations per year in the DNA of the larynx, 39 in the pharynx, 23 in the mouth, 18 in the bladder and 6 in the liver.
Research shows at least five distinct processes by which DNA is damaged by tobacco, the most prevalent of which is found in most types of cancer. It is an acceleration of the cellular pendulum which causes a premature mutation of the cells, explain these geneticists.
Smoking, the largest preventable cause of death, is responsible for at least six million deaths annually worldwide, according to the World Health Organization.
Source : Tdg.ch
