Two gene variations that increase smokers’ risk of lung cancer have been identified by researchers. Smokers with the variants also tend to smoke more and become more dependent on cigarettes, the Canadian study found. Researchers at the Centre for Addiction and Mental Health in Toronto looked at 417 current or former smokers with lung cancer and 443 current or former smokers without cancer. Smokers with the variations in the nicotine metabolic gene (CYP2A6) and the nicotinic gene cluster (CHRNA5-A3-B3) were more likely to have lung cancer, more likely to be more nicotine dependent and were more likely to smoke heavily. The increased risk of lung cancer among people with both variants was the most pronounced among light smokers who smoke 20 or fewer cigarettes a day, the investigators found.
