Genetic variations, along with having a strong lung cancer family history, will lead to a five times increased risk of developing the disease, a new study suggests.
In fact, people who have a family history of lung cancer and two copies of the genetic variations have between a 5.7 and 7.2-fold increased risk of developing lung cancer.
The research was conducted by scientists at Washington University School of Medicine and other American and British institutions.
The findings are published in the Journal of the National Cancer Institute.
For their study, the researchers compared the DNA of 194 people with familial lung cancer (which occurs in three or more direct blood relatives) to that of 219 patients with no history of lung cancer.
When they analyzed each chromosome, which carry human DNA, they found that far more people with familial lung cancer had a specific variation in their DNA on chromosome 15.
Researchers have long believed there is a genetic component to lung cancer because many smokers don't get the disease.
"If we can identify the genetic factors linked to lung cancer in such people before they get the disease, we can take steps to help prevent it," senior study author Dr. Ming You, a researcher at the Siteman Cancer Center at Washington University, said in a statement. "This genetic region might be part of the answer."
The study's findings were not affected by whether the subjects were smokers or non smokers. This means that smoking and the genetic variations are independent risk factors, "and together they might cause an even greater increase in lung cancer risk," You said.
The researchers said this is the fourth such study since April of this year to link this genetic region to the development of lung cancer.
In one study, the same genetic variations were associated with a 30 per cent greater risk of getting what's known as sporadic lung cancer, which occurs when there is no family history of the disease.
The Canadian Cancer Society estimates that nearly 24,000 Canadians will be diagnosed with lung cancer in 2008, and more than 20,000 will die of it.
