Washington: 25 percent of smokers who carry a defect in the BRCA2 gene would be developing lung cancer at some point in their lifetime, a large-scale, international study reveals.
The defect in BRCA2 - best known for its role in breast cancer - increases the risk of developing lung cancer by about 1.8 times.
The researchers, led by a team at The Institute of Cancer Research, London, compared the DNA of 11,348 Europeans with lung cancer and 15,861 without the disease, looking for differences at specific points in their DNA. The team was mainly funded by the US National Institute of Health, with additional support from Cancer Research UK.
The link between lung cancer and defective BRCA2 - known to increase the risk of breast, ovarian and other cancers - was particularly strong in patients with the most common lung cancer sub-type, called squamous cell lung cancer. The researchers also found an association between squamous cell lung cancer and a defect in a second gene, CHEK2, which normally prevents cells from dividing when they have suffered damage to their DNA.
The results suggest that in the future, patients with squamous cell lung cancer could benefit from drugs specifically designed to be effective in cancers with BRCA mutations. A family of drugs called PARP inhibitors have shown success in clinical trials in breast and ovarian cancer patients with BRCA mutations, although it is not known whether they could be effective in lung cancer.
The study has been published in the journal Nature Genetics.