The risk of lung cancer can gravely increase with a genetic defect combined with smoking, according to a report, released by the Institute of Cancer Research in the United Kingdom.
The connection was first uncovered after examining the DNA from over 11,000 Europeans, who were suffering from lung cancer, and around 16,000 people who did not develop the disease.
"Smokers in general have nearly a 15 percent chance of developing lung cancer, far higher than in nonsmokers. Our results show that some smokers with BRCA2 mutations are at an enormous risk of lung cancer -- somewhere in the region of 25 percent over their lifetime," Health Day quoted study leader Richard Houlston, a professor of molecular and popular genetics at the UK institute.
"Lung cancer claims more than a million lives a year worldwide. We know that the single biggest thing we can do to reduce death rates is to persuade people not to smoke, and our new findings make plain that this is even more critical in people with an underlying genetic risk," Houlston stated in an institute news release.
Researchers found that a defect in BRCA2 gene - a breast cancer gene that occurs in around 2 percent of individuals - increases the risk of lung cancer by twofold. They showed that at least one out of four smokers with the genetic defect is likely to develop lung cancer.
Smokers are 40 times likely to develop lung cancer but those with a BRCA2 mutation are close to 80 times more likely, showed the analysis.
"We've known for two decades that inherited mutations in BRCA2 made people more likely to develop breast and ovarian cancer, but these new findings show a greater risk of lung cancer too, especially for people who smoke," BBC quoted Peter Johnson, chief clinician, Cancer Research UK.
However, it is believed that certain drugs, which are used to treat BRCA mutations, could actually aid patients suffering from squamous cell lung cancer. Researchers, however, say that the link did not establish that the genetic defect was accountable to causing lung cancer.
The detailed study of the findings has been published in the journal Nature Genetics.