Smokers with a combination of two specific genes are at increased risk of becoming addicted to nicotine and developing lung cancer, finds a new study.
The cancer risk from these two genes appears to be even higher in smokers who consume 20 or fewer cigarettes a day, researchers found.
CAMH Scientist Dr. Rachel Tyndale and her team studied 417 lung cancer patients and a comparison group of 443 individuals with no cancer - all current or former smokers.
Each individual was classified as having a low, intermediate or high risk of heavier cigarette smoking or developing cancer, depending on which combination of gene variants they had.
The genetic profiles of study participants were linked to reports of cigarette smoking, a standard test of nicotine dependence, and lung cancer presence.
The genetic risk of lung cancer due to these two genes was highest among lighter smokers with both high-risk gene variations, compared to those with one or none of the high-risk gene variations.
"While heavier smoking increases the overall risk for lung cancer (as well as other health problems), our study looked specifically at the effects of these two genes on cancer risk, said Dr. Tyndale, who is also head of CAMH's Pharmacogenetics Lab. "We found the genetic risk from these two genes made a larger contribution among lighter smokers."
The study was recently published in the Journal of the National Cancer Institute.