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Although tobacco is responsible for the vast majority of lung cancers, some heavy smokers seem to be spared from the disease. According to a study published in Nature Genetics, the latter would develop a “prevention system” which would protect them from malignant cells. Explanations.
In France, smoking continues to kill. Nearly 75,000 deaths and 46,363 cases of lung cancer are recorded each year (estimated in 2018). However, nicotine addicts do not seem to develop more genetic mutations than others according to a study published in the journal Nature Genetics.
A new sequencing technique
According to a team of scientists from the Albert Einsten College of Medicine, some heavy smokers seem “protected” disease through an amazing defense mechanism.
To reach this conclusion, the researchers developed a new sequencing technique: SCMDA. It makes it possible to sequence the entire genome of an isolated cell without the sequencing itself inducing mutations.
33 people aged 11 to 86, having more or less smoked in the past (from zero cigarettes to 116 pack-years), took part in the research. The participants were divided into two groups: on one side, the 14 non-smokers aged 11 to 86 years and on the other, the 19 smokers aged 44 to 81 years.
The goal? “Compare the mutational landscape” bronchial basal cells, in other words cells present in the lungs.
These have the particularity “to survive for years, even decades, and therefore can accumulate mutations with age and tobacco”, says the study. Cells at greater risk of becoming cancerous later.
A low number of mutations
However, against all logic, smokers do not accumulate more mutations than non-smokers. “Mutations followed the linear increase in cancer risk until approximately 23 packet-years, after which no further increase in mutation frequency was observed”says the study.
Thereby, “heaviest smokers did not have the highest number of mutations. Our data suggest that these individuals may have survived so long, despite their heavy smoking, because they were able to prevent the accumulation of additional mutations”says Dr. Spivack.
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Repair smokers DNA
These results offer new insights to researchers on the effectiveness of DNA repair mechanisms. A test to identify smokers at risk of lung cancer could thus see the light of day. “This may prove to be an important step towards prevention and early detection of lung cancer risk,” concludes the study.