Three independent genetic studies by University of Texas, deCODE Genetics, and the International Agency for Research on Cancer researchers have found strong evidence that genes influence the risk of developing lung cancer in smokers.

While smoking is still clearly the largest risk factor, some smokers may be as much as 80% more at risk that others, due to gene variants they have on chromosome 15.

The researchers disagree over whether non-smokers possessing the genetic risk factor have an increased risk of developing lung cancer. The “genomewide association study” method used for each study only finds correlations, not the mechanisms of the disease.