Why some smokers don't get cancer

Researchers have identified a set of genetic markers that help even smokers live longer and protect them from deadly diseases such as cancer.

"We identified a set of genetic markers that together seem to promote longevity," said corresponding author of the study Morgan Levine from University of California-Los Angeles.

The study identified a network of single nucleotide polymorphisms, or SNPs (a DNA sequence variation occurring commonly within a population) that allow certain individuals to better withstand environmental damage (like smoking) and mitigate damage.

gThere is evidence that these genes may facilitate lifespan extension by increasing cellular maintenance and repair," Levine noted.

gTherefore, even though some individuals are exposed to high levels of biological stressors, like those found in cigarette smoke, their bodies may be better set up to cope with and repair the damage," Levine pointed out.

Smoking has been shown to have drastic consequences for lifespan and disease progression, and it has been suggested that cigarette exposure may impact the risk of death and disease via its acceleration of the ageing process.

The new findings suggest that longevity, rather than being entirely determined by environmental factors, may be under the regulation of complex genetic networks which influence stress resistance and genomic stability.

Genomic instability also happens to be one of the hallmarks of cancer pathogenesis, and so the same genes that may promote survival among smokers may also be important for cancer prevention.

This is consistent with the findings of the study, which showed that the genes identified were associated with a nearly 11 percent lower cancer prevalence.

The findings appeared in the The Journals of Gerontology, Series A: Biological Sciences and Medical Sciences.