Gene Defect may Determine Likelihood of Lung Cancer in Smokers

A genetic defect can greatly increase the risk of lung cancer, according to a report released by the Institute of Cancer Research in the United Kingdom.

"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," said study leader Richard Houlston, a professor of molecular and popular genetics at the institute, via Health Day. 

The link was first discovered following an analyzation of the DNA from more than 11,000 Europeans with lung cancer and almost 16,000 without the disease.

Researchers found that a defect in the breast cancer BRCA2 gene, which occurs in about 2 percent of individuals, almost doubles the risk of lung cancer. In fact, up to one in four smokers with this genetic defect will develop lung cancer.

"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," said Peter Johnson, Cancer Research UK's chief clinician, via BBC. 

However, researchers believe that certain drugs used to treat BRCA mutations could help patients with squamous cell lung cancer. For instance, PARP inhibitors have shown to be effective in treating breast and ovarian cancers, and may also be able to help treat lung cancer patients, too.

However, researchers note that the link did not prove that the genetic defect was responsible for causing lung cancer.

More information regarding the findings can be seen via the journal Nature Genetics.