The risk of lung cancer rises to 25% in smokers with the BRCA2 gene defect according to a team at the Institute of Cancer Research in London.
The DNA of 11 348 people of European ancestry with lung cancer and 15 861 without the disease was compared and the findings showed a previously unknown link between lung cancer and the defect in BRCA2—best known for its role in breast cancer.
The team was mainly funded by the US National Institutes of Health, with additional support from Cancer Research UK. The results were reported in Nature Genetics this week.
The study found that:
- The link between lung cancer and the defective BRCA2 gene was particularly strong in patients with the most common lung cancer subtype, squamous cell lung cancer (odds ratio 2.47).
- There was an association between squamous cell lung cancer and a defect in a second gene, CHEK2, which normally prevents cells from dividing when their DNA has been damaged.
- An association between common variation at 3q28 and lung adenocarcinoma that had been previously reported only in Asian populations.
The results showed that, in the future, patients with squamous cell lung cancer might 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 who had BRCA mutations, although it is not known whether they could be effective in lung cancer. BMJ 2014;348:g3621
As smokers have higher odds of developing lung cancer (approx 13%) this study shows that adding these odds to a potential genetic susceptibility that raises the odds even further (to approx 25%) makes it all the more desirable to kick the habit.
In the coming weeks we will look at nicotine addiction and various ways to stop smoking.
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